Hagia Sophia (/ˈhɑːɡiə soʊˈfiːə/; from the Greek Αγία Σοφία, pronounced[aˈʝia soˈfia], "Holy Wisdom"; Latin: Sancta Sophia or Sancta Sapientia; Turkish: Ayasofya) is the former Greek Orthodox Christian patriarchal cathedral, later an Ottoman imperial mosque and now a museum (Ayasofya Müzesi) in Istanbul, Turkey. Built in 537 AD at the beginning of the Middle Ages, it was famous in particular for its massive dome. It was the world's largest building and an engineering marvel of its time. It is considered the epitome of Byzantine architecture[1] and is said to have "changed the history of architecture".[2]
The Hagia Sophia construction consists of mostly masonry. The structure is composed of brick and mortar joint that are 1.5 times the width of the bricks. The mortar joints are composed of a combination of sand and minute ceramic pieces displaced very evenly throughout the mortar joints. This combination of sand and ceramic pieces could be considered to be the equivalent of modern concrete at the time.[3]
From the date of its construction in 537 until 1453, it served as an Eastern Orthodox cathedral and the seat of the Ecumenical Patriarch of Constantinople,[4] except between 1204 and 1261, when it was converted by the Fourth Crusaders to a Roman Catholic cathedral under the Latin Empire. The building was later converted into an Ottoman mosque from 29 May 1453 until 1931. It was then secularized and opened as a museum on 1 February 1935.[5] It remained the world's largest cathedral for nearly a thousand years, until Seville Cathedral was completed in 1520.
The current building was originally constructed as a church between 532 and 537 on the orders of the Byzantine Emperor Justinian I and was the third Church of the Holy Wisdom to occupy the site, the prior one having been destroyed by rioters in the Nika Revolt. It was designed by the Greek geometers Isidore of Miletus and Anthemius of Tralles.[6] The church was dedicated to the Wisdom of God, the Logos, the second person of the Trinity,[7] its patronal feast taking place on 25 December, the commemoration of the birth of the incarnation of the Logos in Christ.[7] Although sometimes referred to as Sancta Sophia (as though it were named after Sophia the Martyr), sophia being the phonetic spelling in Latin of the Greek word for wisdom, its full name in Greek is Ναός της Αγίας του Θεού Σοφίας, Naos tēs Hagias tou Theou Sophias, "Shrine of the Holy Wisdom of God".[8][9] The church contained a large collection of relics and featured, among other things, a 15-metre (49ft) silver iconostasis. The focal point of the Eastern Orthodox Church for nearly one thousand years, the building witnessed the excommunication of Patriarch Michael I Cerularius officially communicated by Humbert of Silva Candida, the papal envoy of Pope Leo IX in 1054, an act that is commonly considered the start of the East–West Schism.
In 1453, Constantinople was conquered by the Ottoman Empire under Mehmed the Conqueror, who ordered this main church of Orthodox Christianity converted into a mosque. Although some parts of the city of Constantinople were falling into disrepair, the cathedral was maintained with an amount of money set aside for this purpose. Nevertheless, the Christian cathedral made a strong impression on the new Ottoman rulers and they decided to convert it into a mosque.[10][11] The bells, altar, iconostasis, and other relics were destroyed and the mosaics depicting Jesus, his Mother Mary, Christian saints, and angels were also destroyed or plastered over. Islamic features—such as the mihrab (a niche in the wall indicating the direction toward Mecca, for prayer), minbar (pulpit), and four minarets—were added. It remained a mosque until 1931 when it was closed to the public for four years. It was re-opened in 1935 as a museum by the Republic of Turkey. Hagia Sophia was, as of 2014, the second-most visited museum in Turkey, attracting almost 3.3 million visitors annually.[12] According to data released by the Turkish Culture and Tourism Ministry, Hagia Sophia was Turkey's most visited tourist attraction in 2015.[13]
From its initial conversion until the construction of the nearby Sultan Ahmed Mosque (Blue Mosque of Istanbul) in 1616, it was the principal mosque of Istanbul. The Byzantine architecture of the Hagia Sophia served as inspiration for many other Ottoman mosques, such as the aforementioned mosque, the Şehzade Mosque, the Süleymaniye Mosque, the Rüstem Pasha Mosque and the Kılıç Ali Pasha Complex.
History
Church of Constantius II
The first church on the site was known as the Μεγάλη Ἐκκλησία (Megálē Ekklēsíā, "Great Church"), or in Latin Magna Ecclesia,[14][15] because of its larger dimensions in comparison to the contemporary churches in the City.[7] Inaugurated on 15 February 360 (during the reign of Constantius II) by the Arian bishop Eudoxius of Antioch,[16] it was built next to the area where the imperial palace was being developed. The nearby Hagia Eirene ("Holy Peace") church was completed earlier and served as cathedral until the Great Church was completed. Both churches acted together as the principal churches of the Byzantine Empire.
Writing in 440, Socrates of Constantinople claimed that the church was built by Constantius II, who was working on it in 346.[16] A tradition which is not older than the 7th or 8th century, reports that the edifice was built by Constantine the Great.[16] Zonaras reconciles the two opinions, writing that Constantius had repaired the edifice consecrated by Eusebius of Nicomedia, after it had collapsed.[16] Since Eusebius was bishop of Constantinople from 339 to 341, and Constantine died in 337, it seems possible that the first church was erected by the latter.[16] The edifice was built as a traditional Latin colonnaded basilica with galleries and a wooden roof. It was preceded by an atrium. It was claimed to be one of the world's most outstanding monuments at the time.
The Patriarch of Constantinople John Chrysostom came into a conflict with Empress Aelia Eudoxia, wife of the emperor Arcadius, and was sent into exile on 20 June 404. During the subsequent riots, this first church was largely burned down.[16] Nothing remains of the first church today.
Church of Theodosius II
A second church on the site was ordered by Theodosius II, who inaugurated it on 10 October 415. The basilica with a wooden roof was built by architect Rufinus. A fire started during the tumult of the Nika Revolt and burned the second Hagia Sophia to the ground on 13–14 January 532.
Several marble blocks from the second church survive to the present; among them are reliefs depicting 12 lambs representing the 12 apostles. Originally part of a monumental front entrance, they now reside in an excavation pit adjacent to the museum's entrance after they were discovered in 1935 beneath the western courtyard by A. M. Schneider. Further digging was forsaken for fear of impinging on the integrity of the building.

Remains of the second Hagia Sophia

Basilica of the Hagia Sophia (current structure)

On 23 February 532, only a few weeks after the destruction of the second basilica, Emperor Justinian I decided to build a third and entirely different basilica, larger and more majestic than its predecessors.
Justinian chose geometer and engineer Isidore of Miletus and mathematician Anthemius of Tralles as architects; Anthemius, however, died within the first year of the endeavor. The construction is described in the Byzantine historian Procopius' On Buildings (Peri ktismatōn, Latin: De aedificiis). Columns and other marbles were brought from all over the empire, throughout the Mediterranean. The idea of these columns being spoils from cities such as Rome and Ephesus is a later invention.[17] Even though they were made specifically for Hagia Sophia, the columns show variations in size.[18] More than ten thousand people were employed. This new church was contemporaneously recognized as a major work of architecture. The theories of Heron of Alexandria may have been utilized to address the challenges presented by building such an expansive dome over so large a space. The emperor, together with the Patriarch Menas, inaugurated the new basilica on 27 December 537 – 5 years and 10 months after construction start – with much pomp.[19][20][21] The mosaics inside the church were, however, only completed under the reign of Emperor Justin II (565–578).
Hagia Sophia was the seat of the Orthodox patriarch of Constantinople and a principal setting for Byzantine imperial ceremonies, such as coronations. Like other churches throughout Christendom, the basilica offered sanctuary from persecution to outlaws.
Earthquakes in August 553 and on 14 December 557 caused cracks in the main dome and eastern half-dome. The main dome collapsed completely during a subsequent earthquake on 7 May 558,[22] destroying the ambon, altar, and ciborium. The collapse was due mainly to the unfeasibly high bearing load and to the enormous shear load of the dome, which was too flat.[19] These caused the deformation of the piers which sustained the dome.[19] The emperor ordered an immediate restoration. He entrusted it to Isidorus the Younger, nephew of Isidore of Miletus, who used lighter materials and elevated the dome by "30 feet"[19] (about 6.25 meters or 20.5 feet) – giving the building its current interior height of 55.6 meters (182ft).[23] Moreover, Isidorus changed the dome type, erecting a ribbed dome with pendentives, whose diameter lay between 32.7 and 33.5m.[19] Under Justinian's orders, eight Corinthian columns were disassembled from Baalbek, Lebanon, and shipped to Constantinople around 560.[24] This reconstruction, giving the church its present 6th-century form, was completed in 562. The Byzantine poet Paul the Silentiary composed a long epic poem (still extant), known as Ekphrasis, for the rededication of the basilica presided over by Patriarch Eutychius on 23 December 562 A.D.

In 726, the emperor Leo the Isaurian issued a series of edicts against the veneration of images, ordering the army to destroy all icons – ushering in the period of Byzantine iconoclasm. At that time, all religious pictures and statues were removed from the Hagia Sophia. After a brief reprieve under Empress Irene (797–802), the iconoclasts made a comeback. The Emperor Theophilus (829–842) had two-winged bronze doors with his monograms installed at the southern entrance of the church.
The basilica suffered damage, first in a great fire in 859, and again in an earthquake on 8 January 869, that made one of the half-domes collapse. Emperor Basil I ordered the church repaired.
After the great earthquake of 25 October 989, which collapsed the Western dome arch, Emperor Basil II asked for the Armenian architect Trdat, creator of the cathedrals of Ani and Argina, to direct the repairs.[25] He erected again and reinforced the fallen dome arch, and rebuilt the west side of the dome with 15 dome ribs.[26] The extent of the damage required six years of repair and reconstruction; the church was re-opened on 13 May 994. At the end of the reconstruction, the church's decorations were renovated, including the addition of four immense paintings of cherubs; a new depiction of Christ on the dome; a burial cloth of Christ shown on Fridays, and on the apse a new depiction of the Virgin Mary holding Jesus, between the apostles Peter and Paul.[27] On the great side arches were painted the prophets and the teachers of the church.[27]
In his book De caerimoniis aulae Byzantinae ("Book of Ceremonies"), Emperor Constantine VII (913–919) wrote a detailed account of the ceremonies held in the Hagia Sophia by the emperor and the patriarch.
Upon the capture of Constantinople during the Fourth Crusade, the church was ransacked and desecrated by the Crusaders, as described by the Byzantine historian Niketas Choniates. During the Latin occupation of Constantinople (1204–1261) the church became a Roman Catholic cathedral. Baldwin I of Constantinople was crowned emperor on 16 May 1204 in Hagia Sophia, at a ceremony which closely followed Byzantine practices. Enrico Dandolo, the Doge of Venice who commanded the sack and invasion of the city by the Latin Crusaders in 1204, is buried inside the church, probably in the upper Eastern gallery. In the 19th century, an Italian restoration team placed a cenotaph marker near the probable location, which is still visible today. The marker is frequently mistaken by tourists as being a medieval marker of the actual tomb of the doge.  The real tomb was destroyed by the Ottomans after the conquest of Constantinople in 1453 and subsequent conversion of Hagia Sophia into a mosque.[28]
After the recapture in 1261 by the Byzantines, the church was in a dilapidated state. In 1317, emperor Andronicus II ordered four new buttresses (Pyramídas, Greek: "Πυραμίδας") to be built in the eastern and northern parts of the church, financing them with the inheritance of his deceased wife, Irene.[29]  New cracks developed in the dome after the earthquake of October 1344, and several parts of the building collapsed on 19 May 1346; consequently, the church was closed until 1354, when repairs were undertaken by architects Astras and Peralta.
Mosque (1453–1935)
Constantinople fell to the attacking Ottoman forces on the 29th of May in 1453. In accordance with the traditional custom at the time, Sultan Mehmet II allowed his troops and his entourage three full days of unbridled pillage and looting in the city shortly after it was captured. Once the three days passed, he would then claim its remaining contents for himself.[30][31]
Hagia Sophia was not exempted from the pillage and looting and specifically became its focal point as the invaders believed it to contain the greatest treasures and valuables of the city.[32]
Shortly after Constantinople's defenses collapsed and the Ottoman troops entered the city victoriously, the pillagers and looters made their way to the Hagia Sophia and battered down its doors before storming in.[33] All throughout the period of the siege of Constantinople, the trapped worshippers of the city participated in the Divine Liturgy and the Prayer of the Hours at the Hagia Sophia and the church formed a safe-haven and a refuge for many of those who were unable to contribute to the city's defense, which comprised women, children, the elderly and the sick and the wounded.[34][35] Being hopelessly trapped in the church, the many congregants and yet more refugees inside became spoils-of-war to be divided amongst the triumphant invaders. The building was significantly desecrated and looted to a large extent, with the helpless occupants who sought shelter within the church being either enslaved, physically and sexually violated or simply slaughtered.[32] While most of the elderly and the infirm/wounded and sick were killed, a vast number of women and girls were raped and the remainder (mainly teenage males and young boys) were chained up and sold off into slavery.[33] The church's priests and religious personnel continued to perform Christian rites, prayers and ceremonies until finally being forced to stop by the invaders.[33] When Sultan Mehmet II and his accompanying entourage entered the church, he insisted that it should be converted into a mosque at once. One of the ulama (Islamic scholars) present then climbed up the church's pulpit and recited out the Shahada ("There is no God but Allah, and Mohammed is His prophet"), thus marking the beginning of the gradual conversion of the church into a mosque.[29][36]

As described by several Western visitors (such as the Córdoban nobleman Pero Tafur[37] and the Florentine Cristoforo Buondelmonti),[38] the church was in a dilapidated state, with several of its doors fallen from their hinges; Mehmed II ordered a renovation as well as the conversion. Mehmet attended the first Friday prayer in the mosque on 1 June 1453.[39] Aya Sofya became the first imperial mosque of Istanbul.[40] To the corresponding Waqf were endowed most of the existing houses in the city and the area of the future Topkapı Palace.[29]  From 1478, 2,360 shops, 1,300 houses, 4 caravanserais, 30 boza shops, and 23 shops of sheep heads and trotters gave their income to the foundation.[41] Through the imperial charters of 1520 (AH 926) and 1547 (AH 954) shops and parts of the Grand Bazaar and other markets were added to the foundation.[29]
Before 1481 a small minaret was erected on the southwest corner of the building, above the stair tower.[29] Later, the subsequent sultan, Bayezid II (1481–1512), built another minaret at the northeast corner.[29] One of these collapsed after the earthquake of 1509,[29] and around the middle of the 16th century they were both replaced by two diagonally opposite minarets built at the east and west corners of the edifice.[29]

In the 16th century the sultan Suleiman the Magnificent (1520–1566) brought back two colossal candlesticks from his conquest of Hungary. They were placed on either side of the mihrab. During the reign of Selim II (1566–1574), the building started showing signs of fatigue and was extensively strengthened with the addition of structural supports to its exterior by Ottoman architect Mimar Sinan, who was also an earthquake engineer.[42] In addition to strengthening the historic Byzantine structure, Sinan built the two additional large minarets at the western end of the building, the original sultan's lodge and the Türbe (mausoleum) of Selim II to the southeast of the building in 1576–7 / AH 984. In order to do that, parts of the Patriarchate at the south corner of the building were pulled down the previous year.[29] Moreover, the golden crescent was mounted on the top of the dome,[29] while a respect zone 35 arşin (about 24m) wide was imposed around the building, pulling down all the houses which in the meantime had nested around it.[29]  Later his türbe hosted also 43 tombs of Ottoman princes.[29] In 1594 / AH 1004 Mimar (court architect) Davud Ağa built the türbe of Murad III (1574–1595), where the Sultan and his Valide, Safiye Sultan were later buried.[29] The octagonal mausoleum of their son Mehmed III (1595–1603) and his Valide was built next to it in 1608 / AH 1017 by royal architect Dalgiç Mehmet Aĝa.[43] His son Mustafa I (1617–1618; 1622–1623) converted the baptistery into his türbe.[43]
Murad III had also two large alabaster Hellenistic urns transported from Pergamon and placed on two sides of the nave.[29]
In 1717, under Sultan Ahmed III (1703–1730), the crumbling plaster of the interior was renovated, contributing indirectly to the preservation of many mosaics, which otherwise would have been destroyed by mosque workers.[43] In fact, it was usual for them to sell mosaics stones – believed to be talismans – to the visitors.[43] Sultan Mahmud I ordered the restoration of the building in 1739 and added a medrese (a Koranic school, now the library of the museum), an Imaret (soup kitchen for distribution to the poor) and a library, and in 1740 a Şadirvan (fountain for ritual ablutions), thus transforming it into a külliye, i.e. a social complex. At the same time, a new sultan's lodge and a new mihrab were built inside.
Renovation of 1847
Restoration of the Hagia Sophia was ordered by Sultan Abdülmecid and completed by eight hundred workers between 1847 and 1849, under the supervision of the Swiss-Italian architect brothers Gaspare and Giuseppe Fossati. The brothers consolidated the dome and vaults, straightened the columns, and revised the decoration of the exterior and the interior of the building. The mosaics in the upper gallery were exposed and cleaned, although many were recovered "for protection against further damage". The old chandeliers were replaced by new pendant ones. New gigantic circular-framed disks or medallions were hung on columns. These were inscribed with the names of Allah,  Muhammad, the first four caliphs Abu Bakr, Umar, Uthman and Ali, and the two grandchildren of Muhammad: Hassan and Hussain, by the calligrapher Kazasker Mustafa İzzed Effendi (1801–1877). In 1850 the architects Fossati built a new sultan's lodge or loge in a Neo-Byzantine style connected to the royal pavilion behind the mosque. They also renovated the minbar and mihrab. Outside the main building, the minarets were repaired and altered so that they were of equal height.[44][45] A timekeeper's building and a new madrasah (Islamic school) were built.  When the restoration was finished, the mosque was re-opened with ceremonial pomp on 13 July 1849.
Museum (1935–present)

In 1935, the first Turkish President and founder of the Republic of Turkey, Mustafa Kemal Atatürk, transformed the building into a museum. The carpets were removed and marble floor decorations such as the Omphalion appeared for the first time in centuries, while the white plaster covering many of the mosaics was removed. Nevertheless, the condition of the structure deteriorated, and the World Monuments Fund placed Hagia Sophia on 1996 World Monuments Watch, and again in 1998. The building's copper roof had cracked, causing water to leak down over the fragile frescoes and mosaics. Moisture entered from below as well. Rising ground water had raised the level of humidity within the monument, creating an unstable environment for stone and paint. The WMF secured a series of grants from 1997 to 2002 for the restoration of the dome. The first stage of work involved the structural stabilization and repair of the cracked roof, which was undertaken with the participation of the Turkish Ministry of Culture. The second phase, the preservation of the dome's interior, afforded the opportunity to employ and train young Turkish conservators in the care of mosaics. By 2006, the WMF project was complete, though many other areas of Hagia Sophia continue to require significant stability improvement, restoration and conservation.[46] Hagia Sophia is currently (2014) the second most visited museum in Turkey, attracting almost 3.3 million visitors annually.[12]
Although use of the complex as a place of worship (mosque or church) was strictly prohibited,[47]  in 2006 the Turkish government allowed the allocation of a small room in the museum complex to be used as a prayer room for Christian and Muslim museum staff,[48] and since 2013 from the minarets of the museum the muezzin sings the call to prayer twice per day, in the afternoon.[49]
In 2007, Greek American politician Chris Spirou launched an international organization "Free Agia Sophia Council" championing the cause of restoring the building to its original function as a Christian church.[50][51][52] Since the early 2010s, several campaigns and government high officials, notably Turkey's deputy prime minister Bülent Arınç in November 2013, have been demanding that Hagia Sophia be converted into a mosque again.[53][54][55] In 2015, in retaliation for the acknowledgment by Pope Francis of the Armenian Genocide, the Mufti of Ankara, Mefail Hızlı, stated that he believes the conversion of Hagia Sophia into a mosque will be accelerated.[56][57]
On July 1, 2016, Muslim prayers were held again in the Hagia Sophia for the first time in 85 years.[58]
On May 13, 2017, a large group of people organized by the Anatolia Youth Association (AGD), gathered in front of Hagia Sophia and prayed the morning prayer with a call for the reconversion of the museum into a mosque.[59] On June 21, 2017, Presidency of Religious Affairs (Diyanet) organized a special program, which included the recitation of the Quran and prayers in Hagia Sofia, to mark the Laylat al-Qadr, the program was broadcast live by state-run television TRT.[60]
In March 31, 2018, Turkish president Recep Tayyip Erdoğan recited the first verse of the Quran in the Hagia Sophia, dedicating the prayer to the "souls of all who left us this work as inheritance, especially Istanbul's conqueror," strengthening the political movement to make the Hagia Sophia a mosque once again, which would reverse Atatürk's measure of turning the Hagia Sophia into a secular museum.[61]
Timeline of Hagia Sophia
360 A.D – Inauguration of Hagia Sophia, under the rule of Constantius II.
404 A.D – The original roof was destroyed in a fire.
415 A.D – Hagia Sophia was restored and rededicated by Theodosius II.
532 A.D – Hagia Sophia was burned down once again. The structure was completely destroyed alongside various other churches. After a mere 93 days, construction of the Hagia Sophia began.
537 A.D – The reconstruction was completed with the lavish decorations and ornaments
553 A.D – An earthquake shook Hagia Sophia, weakening the crown of Eastern arch.
558 A.D – Another earthquake hit, causing a break between the two halves. A few months after, the main dome collapsed alongside the eastern semidome. This caused the destruction of the ambo, ciborium, and the Holy Table.
562 A.D – Reconstruction was completed.
726 A.D – Hagia Sophia was stripped of religious illustrations and sculptural work.
842 A.D – St Sophia was finally re-installed. Commencing the redecoration of Hagia Sophia.
859 A.D – A great fire damaged the Hagia Sophia.
869 A.D – An earthquake caused a half dome to collapse.
989 A.D – Another massive earthquake caused the collapse of the western dome.
994 A.D – Hagia Sophia was reopened after reconstruction took place.
1204 A.D – Hagia Sophia became a Roman Catholic Cathedral.
1261 A.D – Hagia Sophia was converted to an Orthodox Church again.
1344 A.D – An earthquake caused severe damage throughout the striation
1346 A.D – Various parts of the building collapsed and the church was closed.
1354 A.D – Hagia Sophia reopened after construction.
1453 A.D – Following the fall of Constantinople, Mehmed the Conqueror orders the conversion of Hagia Sophia into a mosque. Τhe Divine Service in Hagia Sophia at the time of the Salvation was interrupted.
1573 A.D – The exterior was significantly strengthened and altered to follow the customary mosque appearance.
1717 A.D – Renovations on the interior began.
1734 A.D – Hagia Sophia had additions to restorations, such as the building of a library and a Quranic School.
1847 A.D – The structure underwent another restoration
1849 A.D – the mosque was reopened.
1919 A.D. Τhe Divine Service in Hagia Sophia, which had interrupted after the Salvation in 1453 A.D., was continued and completed by a Greek military priest.[62]
1935 A.D – the building was transformed into a museum.
[63]
Architecture

Hagia Sophia is one of the greatest surviving examples of Byzantine architecture.[1] Its interior is decorated with mosaics and marble pillars and coverings of great artistic value. The temple itself was so richly and artistically decorated that Justinian proclaimed, "Solomon, I have outdone thee!" (Νενίκηκά σε Σολομών). Justinian himself had overseen the completion of the greatest cathedral ever built up to that time, and it was to remain the largest cathedral for 1,000 years up until the completion of the cathedral in Seville in Spain.[64]
Justinian's basilica was at once the culminating architectural achievement of late antiquity and the first masterpiece of Byzantine architecture. Its influence, both architecturally and liturgically, was widespread and enduring in the Eastern Orthodox, Roman Catholic, and Muslim worlds alike.
The vast interior has a complex structure. The nave is covered by a central dome which at its maximum is 55.6m (182ft 5in) from floor level and rests on an arcade of 40 arched windows. Repairs to its structure have left the dome somewhat elliptical, with the diameter varying between 31.24 and 30.86m (102ft 6in and 101ft 3in).
At the western entrance side and eastern liturgical side, there are arched openings extended by half domes of identical diameter to the central dome, carried on smaller semi-domed exedras; a hierarchy of dome-headed elements built up to create a vast oblong interior crowned by the central dome, with a clear span of 76.2m (250ft).[1]
Interior surfaces are sheathed with polychrome marbles, green and white with purple porphyry, and gold mosaics. The exterior, clad in stucco, was tinted yellow and red during restorations in the 19th century at the direction of the Fossati architects.
Narthex and portals
The Imperial Gate was the main entrance between the exo- and esonarthex. It was reserved exclusively for the Emperor. The Byzantine mosaic above the portal depicts Christ and an unnamed emperor. A long ramp from the northern part of the outer narthex leads up to the upper gallery.
Upper gallery
Throughout history the Hagia Sophia has been a victim to natural disasters, such as earthquakes, and has also fallen victim to vandalism. Structural damage can easily be seen on its exterior surface. To ensure that the Hagia Sophia did not ensue any damage on the interior of the building, studies have been conducted using ground penetrating radar within the gallery of the Hagia Sophia. With the use of GPR (ground penetrating radar), teams discovered weak zones within the Hagia Sophia's gallery and also concluded that the curvature of the vault dome has been shifted out of proportion, compared to its original angular orientation.[65]
The upper gallery is laid out in a horseshoe shape that encloses the nave until the apse. Several mosaics are preserved in the upper gallery, an area traditionally reserved for the Empress and her court. The best-preserved mosaics are located in the southern part of the gallery.
The upper gallery contains runic graffiti presumed to be from the Varangian Guard.
Dome

The dome of Hagia Sophia has spurred particular interest for many art historians, architects and engineers because of the innovative way the original architects envisioned it. The dome is carried on four spherical triangular pendentives, one of the first large-scale uses of them. The pendentives are the corners of the square base of the dome, which curve upwards into the dome to support it, restraining the lateral forces of the dome and allowing its weight to flow downwards.[66][67] It was the largest pendentive dome in the world until the completion of St. Peter's Basilica, and has a much lower height than any other dome of such a large diameter.
The great dome at the Hagia Sophia is one hundred and seven feet in diameter and is only two feet thick. The main building material for the Hagia Sophia composed of brick and mortar. Brick aggregate was used to make roofs easier to construct. The aggregate weighs one hundred and fifty pounds per cubic foot, an average weight of masonry construction at the time. Due to the materials plasticity it was chosen over cut stone due to the fact that aggregate can be used over a longer distance.[68]
The weight of the dome remained a problem for most of the building's existence. The original cupola collapsed entirely after the earthquake of 558; in 563 a new dome was built by Isidore the younger, a nephew of Isidore of Miletus. Unlike the original, this included 40 ribs and was raised 20 feet, in order to lower the lateral forces on the church walls. A larger section of the second dome collapsed as well, in two episodes, so that today only two sections of the present dome, in the north and south side, still date from the 562 reconstructions. Of the whole dome's 40 ribs, the surviving north section contains eight ribs, while the south section includes six ribs.[69]
Although this design stabilizes the dome and the surrounding walls and arches, the actual construction of the walls of Hagia Sophia weakened the overall structure. The bricklayers used more mortar than brick, which is more effective if the mortar was allowed to settle as the building would have been more flexible; however, the builders raced to complete the building and left no time for the mortar to cure before they began the next layer. When the dome was erected, its weight caused the walls to lean outward because of the wet mortar underneath. When Isidore the Younger rebuilt the fallen cupola, he had first to build up the interior of the walls to make them vertical again. Additionally, the architect raised the height of the rebuilt dome by approximately sixm (20 feet) so that the lateral forces would not be as strong and its weight would be transmitted more effectively down into the walls. Moreover, he shaped the new cupola like a scalloped shell or the inside of an umbrella, with ribs that extend from the top down to the base. These ribs allow the weight of the dome to flow between the windows, down the pendentives, and ultimately to the foundation.[70]
Hagia Sophia is famous for the light that reflects everywhere in the interior of the nave, giving the dome the appearance of hovering above. This effect was achieved by inserting forty windows around the base of the original structure. Moreover, the insertion of the windows in the dome structure lowers its weight.[70]
Minarets
The minarets were an Ottoman addition and not part of the original church's Byzantine design. They were built for notification of invitations for prayers and announcements. Mehmed had built a minaret made from wood over one of the half domes soon after Hagia Sophia's conversion from a cathedral to a mosque. This minaret does not exist today. One of the minarets (at southwest) was built from red brick and can be dated back from the Fatih Sultan Mehmed period or Beyazıd II period. The other three were built from white limestone and sandstone, of which the slender northeast column was erected by Sultan Bayezid II during the Selim II period, while the two identical larger minarets to the west were erected by Sultan Selim II and designed by the famous Ottoman architect Mimar Sinan. Both are 60 metres in height, and with their thick and massif patterns, complete Hagia Sophia's main structure. Many ornaments and details were added to these minarets on repairs during the 15th, 16th, and 19th centuries, which reflect each period's characteristics and ideals.[71][72]
Buttresses
Numerous buttresses have been added throughout the centuries. The flying buttresses to the west of the building, although thought to have been constructed by the Crusaders upon their visit to Constantinople, are actually built during the Byzantine era. This shows that the Byzantines had prior knowledge of flying buttresses which can also be seen at Hosios Loukas in Central Greece, the Rotunda of Galerius in Thessaloniki, and San Vitale in Ravenna.[70] Other buttresses were constructed during the Ottoman times under the guidance of the architect Sinan. A total of 24 buttresses were added.[73]
Notable elements and decorations
Originally, under Justinian's reign, the interior decorations consisted of abstract designs on marble slabs on the walls and floors, as well as mosaics on the curving vaults. Of these mosaics, one can still see the two archangels Gabriel and Michael in the spandrels of the bema. There were already a few figurative decorations, as attested by the eulogy of Paul the Silentiary. The spandrels (corners) of the gallery are faced in inlaid thin slabs (opus sectile), showing patterns and figures of flowers and birds in precisely cut pieces of white marble set against a background of black marble. In later stages, figurative mosaics were added, which were destroyed during the iconoclastic controversy (726–843). Present mosaics are from the post-iconoclastic period.
Apart from the mosaics, a large number of figurative decorations were added during the second half of the 9th century: an image of Christ in the central dome; Orthodox saints, prophets and Church Fathers in the tympana below; historical figures connected with this church, such as Patriarch Ignatius; some scenes from the gospel in the galleries.
Basil II let artists paint on each of the four pendentives a giant six-winged Cherub.[27] The Ottomans covered their face with a golden halo,[27] but in 2009 one of them was restored to the original state.[74]

The Loge of the Empress. The columns are made of green Thessalian stone
Lustration urn from Pergamon
Marble Door
The wishing column

Loggia of the Empress
The Loggia of the Empress is located in the centre of the upper enclosure, or gallery, of the Hagia Sophia. From there the empress and the court-ladies would watch the proceedings down below. A round green stone marks the spot where the throne of the empress stood.[75][76]
Lustration urns
Two huge marble lustration (ritual purification)  urns were brought from Pergamon during the reign of Sultan Murad III. From the Hellenistic period, they are carved from single blocks of marble.[29]
Marble Door
The Marble Door inside the Hagia Sophia is located in the southern upper enclosure or gallery. It was used by the participants in synods, who entered and left the meeting chamber through this door. It is said that each side is symbolic and that one side represents heaven while the other represents hell. Its panels are covered in fruits and fish motives. The door opens into a space that was used as a venue for solemn meetings and important resolutions of patriarchate officials.[77]
The Nice Door
The Nice Door is the oldest architectural element found in the Hagia Sophia dating back to the 2nd century BC. The decorations are of reliefs of geometric shapes as well as plants that are believed to have come from a pagan temple in Tarsus, Mersin now modern-day Turkey. It was incorporated into the building by Emperor Theophilos in 838AD where it is placed in the south exit in the inner narthex.[78]
The Emperor Door
The Emperor Door is the door that would be used solely by the Emperor as well as his personal bodyguard and retinue. It is the largest door in the Hagia Sophia and has been dated to the 6th century. It is about 7 meters long and Eastern Roman sources say it was made with wood from Noah's Ark.[79]
Wishing column
At the northwest of the building, there is a column with a hole in the middle covered by bronze plates. This column goes by different names; the perspiring column, the wishing column, the sweating column or the crying column. The column is said to be damp when touched and have supernatural powers.[80] The legend states that since St. Gregory the Miracle Worker appeared near the column in the year 1200, it has been moist. It is believed that touching the moisture cures many illnesses.[81][82]
Mosaics

The first mosaics which adorned the church were only completed during the reign of Justin II.[83] Many of the non-figurative mosaics in the church come from this period. Most of the mosaics, however, were completed after the end of the periods of Byzantine Iconoclasm in 843 AD.
During the Sack of Constantinople in 1204, the Latin Crusaders vandalized valuable items in every important Byzantine structure of the city, including the golden mosaics of the Hagia Sophia. Many of these items were shipped to Venice, whose Doge, Enrico Dandolo, had organized the invasion and sack of Constantinople after an agreement with Prince Alexios Angelos, the son of a deposed Byzantine emperor.
19th-century restoration
Following the building's conversion into a mosque in 1453, many of its mosaics were covered with plaster, due to Islam's ban on representational imagery. This process was not completed at once, and reports exist from the 17th century in which travelers note that they could still see Christian images in the former church. In 1847–49, the building was restored by two Swiss-Italian Fossati brothers, Gaspare and Giuseppe, and Sultan Abdülmecid allowed them to also document any mosaics they might discover during this process which were later archived in Swiss libraries.[84] This work did not include repairing the mosaics and after recording the details about an image, the Fossatis painted it over again. The Fossatis restored the mosaics of the two hexapteryga (singular Greek: ἑεξαπτέρυγον, pr. hexapterygon, six-winged angel; it is uncertain whether they are seraphim or cherubim) located on the two east pendentives, covering their faces again before the end of the restoration.[85] The other two placed on the west pendentives are copies in paint created by the Fossatis since they could find no surviving remains of them.[85] As in this case, the architects reproduced in paint damaged decorative mosaic patterns, sometimes redesigning them in the process. The Fossati records are the primary sources about a number of mosaic images now believed to have been completely or partially destroyed in the 1894 Istanbul earthquake. These include a mosaic over a now-unidentified Door of the Poor, a large image of a jewel-encrusted cross, and a large number of images of angels, saints, patriarchs, and church fathers. Most of the missing images were located in the building's two tympana.
One mosaic they documented is Christ Pantocrator in a circle, which would indicate it to be a ceiling mosaic, possibly even of the main dome which was later covered and painted over with Islamic calligraphy that expounds God as the light of the universe. The drawings of the Hagia Sophia mosaics are today kept in the Cantonal Archive of Ticino.[86]
20th-century restoration
A large number of mosaics were uncovered in the 1930s by a team from the Byzantine Institute of America led by Thomas Whittemore. The team chose to let a number of simple cross images remain covered by plaster but uncovered all major mosaics found.
In 2000, The National Technical University of Athens has begun to use Non Destructive Techniques along with infrared technology to scan walls of the Hagia Sophia to locate mosaics that have been previously covered with plaster. The National Technical University of Athens is using infrared technology, to assess the damage mosaics have taken within the Hagia Sophia beneath the plaster. The National Technical University of Athens uses categories such as water intrusion to determine a mosaics current state of condition.[87]
Because of its long history as both a church and a mosque, a particular challenge arises in the restoration process. Christian iconographic mosaics can be uncovered, but often at the expense of important and historic Islamic art. Restorers have attempted to maintain a balance between both Christian and Islamic cultures. In particular, much controversy rests upon whether the Islamic calligraphy on the dome of the cathedral should be removed, in order to permit the underlying Pantocrator mosaic of Christ as Master of the World, to be exhibited (assuming the mosaic still exists).[88]
The Hagia Sophia has been a victim to natural disasters that have caused deterioration to the buildings structure and walls. The deterioration of the Hagia Sophia's walls can be directly relate to salt crystallization. The crystallization of salt is due to an intrusion of rainwater that is at fault for the Hagia Sophia's deteriorating inner and outer walls. Diverting excess rainwater is the main solution to solve the deteriorating walls at the Hagia Sophia.[89]
Built between 532-537 a subsurface structure under the Hagia Sophia has been under investigation, using LaCoste-Romberg gravimeters to determine the depth of the subsurface structure and to discover other hidden cavities beneath the Hagia Sophia.The hidden cavities have also acted as a support system against earthquakes. With these findings using the LaCoste-Romberg gravimeters, it was also discovered that the Hagia Sophia's foundation is built on a slope of natural rock.[90]
Imperial Gate mosaic

The Imperial Gate mosaic is located in the tympanum above that gate, which was used only by the emperors when entering the church. Based on style analysis, it has been dated to the late 9th or early 10th century. The emperor with a nimbus or halo could possibly represent emperor Leo VI the Wise or his son Constantine VII Porphyrogenitus bowing down before Christ Pantocrator, seated on a jeweled throne, giving His blessing and holding in His left hand an open book.[91] The text on the book reads as follows: "Peace be with you. I am the light of the world". (John 20:19; 20:26; 8:12) On each side of Christ's shoulders is a circular medallion: on His left the Archangel Gabriel, holding a staff, on His right His Mother Mary.[92]
Southwestern entrance mosaic

The southwestern entrance mosaic, situated in the tympanum of the southwestern entrance, dates from the reign of Basil II.[93] It was rediscovered during the restorations of 1849 by the Fossatis. The Virgin sits on a throne without a back, her feet resting on a pedestal, embellished with precious stones. The Child Christ sits on her lap, giving His blessing and holding a scroll in His left hand. On her left side stands emperor Constantine in ceremonial attire, presenting a model of the city to Mary. The inscription next to him says: "Great emperor Constantine of the Saints". On her right side stands emperor Justinian I, offering a model of the Hagia Sophia. The medallions on both sides of the Virgin's head carry the monograms MP and ΘΥ, an abbreviation of "Mētēr" and "Theou", meaning "Mother of God".[94]

Apse mosaics

The Virgin and Child mosaic was the first of the post-iconoclastic mosaics. It was inaugurated on 29 March 867 by Patriarch Photius and the emperors Michael III and Basil I. This mosaic is situated in a high location on the half dome of the apse. Mary is sitting on a throne without a back, holding the Child Jesus on her lap. Her feet rest on a pedestal. Both the pedestal and the throne are adorned with precious stones. The portraits of the archangels Gabriel and Michael (largely destroyed) in the bema of the arch also date from the 9th century. The mosaics are set against the original golden background of the 6th century. These mosaics were believed to be a reconstruction of the mosaics of the 6th century that were previously destroyed during the iconoclastic era by the Byzantines of that time, as represented in the inaugural sermon by the patriarch Photios. However, no record of figurative decoration of Hagia Sophia exists before this time.[95]
Emperor Alexander mosaic
The Emperor Alexander mosaic is not easy to find for the first-time visitor, located on the second floor in a dark corner of the ceiling. It depicts Emperor Alexander in full regalia, holding a scroll in his right hand and a globus cruciger in his left. A drawing by the Fossatis showed that the mosaic survived until 1849 and that Thomas Whittemore, founder of the Byzantine Institute of America who was granted permission to preserve the mosaics, assumed that it had been destroyed in the earthquake of 1894. Eight years after his death, the mosaic was discovered in 1958 largely through the researches of Robert Van Nice. Unlike most of the other mosaics in Hagia Sophia, which had been covered over by ordinary plaster, the Alexander mosaic was simply painted over and reflected the surrounding mosaic patterns and thus was well hidden. It was duly cleaned by the Byzantine Institute's successor to Whittemore, Paul A. Underwood.[96][97]
Empress Zoe mosaic

The Empress Zoe mosaic on the eastern wall of the southern gallery date from the 11th century. Christ Pantocrator, clad in the dark blue robe (as is the custom in Byzantine art), is seated in the middle against a golden background, giving His blessing with the right hand and holding the Bible in His left hand. On either side of His head are the monograms IC and XC, meaning Iēsous Christos. He is flanked by Constantine IX Monomachus and Empress Zoe, both in ceremonial costumes. He is offering a purse, as a symbol of donation, he made to the church, while she is holding a scroll, symbol of the donations she made. The inscription over the head of the emperor says: "Constantine, pious emperor in Christ the God, king of the Romans, Monomachus". The inscription over the head of the empress reads as follows: "Zoë, the very pious Augusta". The previous heads have been scraped off and replaced by the three present ones. Perhaps the earlier mosaic showed her first husband Romanus III Argyrus or her second husband Michael IV. Another theory is that this mosaic was made for an earlier emperor and empress, with their heads changed into the present ones.[98]
Comnenus mosaic

The Comnenus mosaic, also located on the eastern wall of the southern gallery, dates from 1122. The Virgin Mary is standing in the middle, depicted, as usual in Byzantine art, in a dark blue gown. She holds the Child Christ on her lap. He gives His blessing with His right hand while holding a scroll in His left hand. On her right side stands emperor John II Comnenus, represented in a garb embellished with precious stones. He holds a purse, symbol of an imperial donation to the church. Empress Irene stands on the left side of the Virgin, wearing ceremonial garments and offering a document. Their eldest son Alexius Comnenus is represented on an adjacent pilaster. He is shown as a beardless youth, probably representing his appearance at his coronation aged seventeen. In this panel, one can already see a difference with the Empress Zoe mosaic that is one century older. There is a more realistic expression in the portraits instead of an idealized representation. The Empress, Saint Irene (born Piroska), daughter of Ladislaus I of Hungary is shown with plaited blond hair, rosy cheeks, and grey eyes, revealing her Hungarian descent. The emperor is depicted in a dignified manner.[99]
Deësis mosaic

The Deësis mosaic (Δέησις, "Entreaty") probably dates from 1261. It was commissioned to mark the end of 57 years of Roman Catholic use and the return to the Orthodox faith. It is the third panel situated in the imperial enclosure of the upper galleries. It is widely considered the finest in Hagia Sophia, because of the softness of the features, the humane expressions and the tones of the mosaic. The style is close to that of the Italian painters of the late 13th or early 14th century, such as Duccio. In this panel the Virgin Mary and John the Baptist (Ioannes Prodromos), both shown in three-quarters profile, are imploring the intercession of Christ Pantocrator for humanity on Judgment Day. The bottom part of this mosaic is badly deteriorated.[100] This mosaic is considered as the beginning of the Renaissance in Byzantine pictorial art.[101]
Northern tympanum mosaics
The northern tympanum mosaics feature various saints. They have been able to survive due to the very high and unreachable location. They depict Saints John Chrysostom and Ignatius the Younger standing, clothed in white robes with crosses, and holding richly jeweled Holy Bibles. The names of each saint are given around the figures in Greek, in order to enable an identification for the visitor. The other mosaics in the other tympana have not survived probably due to the frequent earthquakes as opposed to any deliberate destruction by the Ottoman conquerors.[102]
Dome Angel Figure Mosaic
This features four unidentical angel figures. It is believed that these on headed six winged angels, also known as seraphim, protect the lords throne in heaven. There are angels in the east composed in mosaics as where the ones in the west were damaged during the Eastern Roman Period, they have been renewed as fresco. During the ottoman period the angels faces were covered with metallic lids in the shape of stars, but were removed to reveal the faces in 2009 during renovations.[103]
Other burials
Mustafa I, in the courtyard
Enrico Dandolo, in the east gallery
Gallery

Mosaics with geometric pattern decorate the upper imperial gallery
Detail of Deësis mosaic
Mosaic in the northern tympanum depicting Saint John Chrysostom
Drawing by the Fossati brother depicting some mosaics
Another drawing by the Fossati brothers depicting mosaic of six patriarchs in the southern tympanum
One of the mighty stone columns with metal clasps
Interior of the Hagia Sophia by John Singer Sargent, 1891
Detail of relief on the Marble Door.
Interior view of the Hagia Sophia, showing Islamic elements on the top of the main dome ().
Haghia Sofia from Adriaan Reland (1676–1718): Verhandeling van de godsdienst der Mahometaanen, 1719
Hagia Sophia during its time as a mosque. Illustration by Gaspare Fossati and Louis Haghe from 1852.
Interior panorama of the Hagia Sophia ().
Circa 1900 photograph, from its time as a mosque.
The face of the Hexapterygon (six-winged angel) on the northeast pendentive (upper left), discovered but covered again by Gaspare Fossati during its restoration, is visible again ().
Imperial Gate
19th-century marker of the tomb of Enrico Dandolo, the Doge of Venice who commanded the Sack of Constantinople in 1204, inside the Hagia Sophia

Works modeled on the Hagia Sofia
Many religious structures have been modeled on the Hagia Sophia's core structure of a large central dome resting on pendentives and buttressed by two semi-domes. A notable Venetian example is the High Altar of Santa Maria della Salute.
Several mosques commissioned by the Ottoman dynasty closely mimic the geometry of the Hagia Sophia, including the Süleymaniye Mosque and the Bayezid II Mosque. In many cases, Ottoman architects preferred to surround the central dome with four semi-domes rather than two. This is true in the Sultan Ahmed Mosque, the New Mosque (Istanbul), and the Fatih Mosque. Like the original plan of the Hagia Sophia, many of these mosques are also entered through a colonnaded courtyard. However, the courtyard of the Hagia Sophia no longer exists.
Many Neo-Byzantine churches are modeled on the Hagia Sophia. The Kronstadt Naval Cathedral and Poti Cathedral closely replicate the internal geometry of the Hagia Sophia. The interior of the Kronstadt Naval Cathedral is a nearly 1-to-1 copy of the Hagia Sophia. The marble revetment also closely mimics the source work.  Like Ottoman mosques, many churches based on the Hagia Sophia include four semi-domes rather than two, such as the Church of Saint Sava in Belgrade.
Several churches combine the layout of the Hagia Sophia with a Latin cross plan. For instance, the Cathedral Basilica of Saint Louis (St. Louis), where the transept is formed by two semi-domes surrounding the main dome. This church also closely emulates the column capitals and mosaic styles of the Hagia Sophia. Other similar examples include the Alexander Nevsky Cathedral, Sofia, Saint Clement Catholic Church, Chicago, and Basilica of the National Shrine of the Immaculate Conception.
The Catedral Metropolitana Ortodoxa in São Paulo and the Église du Saint-Esprit (Paris) closely follow the interior layout of the Hagia Sophia. Both include four semi-domes, but the two lateral semi-domes are very shallow. In terms of size, the Église du Saint-Esprit is about two thirds the scale of the Hagia Sophia.
Synagogues based on the Hagia Sophia include the Congregation Emanu-El (San Francisco), Great Synagogue of Florence, and Hurva Synagogue.
See also

Oldest churches in the world
List of megalithic sites
Conversion of non-Muslim places of worship into mosques
Pendentive—Architectural element
List of Byzantine inventions
Islam in Turkey
Ottoman architecture
List of mosques in Istanbul
List of mosques in Turkey
List of mosques
Sultan Ahmed Mosque
History of Roman and Byzantine domes
Related Buildings:
Church of the Holy Apostles—the second most important church of Constantinople
Hagia Irene—neighbouring church
Little Hagia Sophia—a 6th-century Byzantine church, now mosque, that might have been built by the same architects as Hagia Sophia
Church of St. Polyeuctus – An earlier church that may have served as a model for the Hagia Sophia
Chora Church — Byzantine church in Istanbul notable for its well preserved Paleologan mosaics, now a museum too
Pammakaristos Church: its parekklesion—also a museum—is decorated with beautiful mosaics
Haseki Hürrem Sultan Hamamı—bath commissioned by Roxelana for the Hagia Sophia community
Caferağa Medresseh—former Koranic school next to Hagia Sophia
Soğukçeşme Sokağı—historical street between the Hagia Sophia and Topkapı Palace
Saint Sophia Cathedral in Kiev
Saint Sophia Cathedral in Novgorod
Saint Sophia Cathedral in Polotsk
Hagia Sophia Church (Sofia)

Bibliography

 , also known as Church of Holy Wisdom.
Hagia Sophia. . Accessed 23 Sept 2014.

.

Runciman, Steven (1965). , 1453. Cambridge: Cambridge University Press. p.145. ISBN0-521-39832-0.

Further reading

Harris, Jonathan, Constantinople: Capital of Byzantium. Hambledon/Continuum (2007). ISBN978-1-84725-179-4

Scharf, Joachim:Der Kaiser in Proskynese. Bemerkungen zur Deutung des Kaisermosaiks im Narthex der Hagia Sophia von Konstantinopel. In: Festschrift Percy Ernst Schramm zu seinem siebzigsten Geburtstag von Schülern und Freunden zugeeignet, Wiesbaden 1964, S. 27–35.

Weitzmann, Kurt, ed., , no. 592, 1979, Metropolitan Museum of Art, New York, ISBN978-0-87099-179-0
Articles
Bordewich, Fergus M., , Smithsonian magazine, December 2008
Mosaics
Hagia Sophia, .

 by Procopius, Buildings (De Aedificiis), published in 561.


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A typhoon is a mature tropical cyclone that develops between 180° and 100°E in the Northern Hemisphere.  This region is referred to as the Northwestern Pacific Basin,[1] and is the most active tropical cyclone basin on Earth, accounting for almost one-third of the world's annual tropical cyclones. For organizational purposes, the northern Pacific Ocean is divided into three regions: the eastern (North America to 140°W), central (140°W to 180°), and western (180° to 100°E). The Regional Specialized Meteorological Center (RSMC) for tropical cyclone forecasts is in Japan, with other tropical cyclone warning centers for the northwest Pacific in Hawaii (the Joint Typhoon Warning Center), the Philippines and Hong Kong. While the RSMC names each system, the main name list itself is coordinated among 18 countries that have territories threatened by typhoons each year.
A typhoon differs from a cyclone or hurricane only on the basis of location.[2] A hurricane is a storm that occurs in the Atlantic Ocean or northeastern Pacific Ocean, a typhoon occurs in the northwestern Pacific Ocean, and a tropical cyclone occurs in the south Pacific or Indian Ocean.[2]
Within the northwestern Pacific, there are no official typhoon seasons as tropical cyclones form throughout the year. Like any tropical cyclone, there are a few main requirements for typhoon formation and development: (1) sufficiently warm sea surface temperatures, (2) atmospheric instability, (3) high humidity in the lower to middle levels of the troposphere, (4) enough Coriolis effect to develop a low pressure center, (5) a pre-existing low level focus or disturbance, and (6) a low vertical wind shear. While the majority of storms form between June and November, a few storms do occur between December and May (although tropical cyclone formation is at a minimum during that time). On average, the northwestern Pacific features the most numerous and intense tropical cyclones globally. Like other basins, they are steered by the subtropical ridge towards the west or northwest, with some systems recurving near and east of Japan. The Philippines receive the brunt of the landfalls, with China and Japan being impacted slightly less. Some of the deadliest typhoons in history have struck China. Southern China has the longest record of typhoon impacts for the region, with a thousand-year sample via documents within their archives. Taiwan has received the wettest known typhoon on record for the northwest Pacific tropical cyclone basins.

Nomenclature
Etymology and usage
The term typhoon is the regional name in the northwest Pacific for a severe (or mature) tropical cyclone,[3] whereas hurricane is the regional term in the northeast Pacific and northern Atlantic.[4] Elsewhere this is called a tropical cyclone, severe tropical cyclone, or severe cyclonic storm.[5]
The Oxford English Dictionary[6] cites Urdu ṭūfān and Chinese tai fung giving rise to several early forms in English. The earliest forms -- "touffon", later "tufan", "tuffon", and others—derive from Urdu ṭūfān, with citations as early as 1588.  From 1699 appears "tuffoon", later "tiffoon", derived from Chinese with spelling influenced by the older Urdu-derived forms.  The modern spelling "typhoon" dates to 1820, preceded by "tay-fun" in 1771 and "ty-foong", all derived from the Chinese tai fung.
The Urdu source word توفان ṭūfān ("violent storm"; cognate to Hindi तूफ़ान (tūfān))[7] comes from the Persian (Persian: توفان/طوفان tūfān meaning "storm" which comes from the verb (Persian: توفیدن/طوفیدن tūfīdan (Persian: توفیدن/طوفیدن, "to roar, to blow furiously"). The word طوفان (ṭūfān) is also derived from Arabic as coming from ṭāfa, to turn round.[6]
The Chinese source is the word tai fung or taifeng[7] (simplified Chinese:台风; traditional Chinese:颱風; pinyin:táifēng).   The modern Japanese word, 台風 (たいふう, taifuu), is also derived from Chinese.  The first character is normally used to mean "pedestal" or "stand", but is actually a simplification of the older Chinese character 颱, which means "typhoon"; thus the word originally meant "typhoon wind".
The Ancient Greek Τυφῶν (Typhôn, "Typhon") is not unrelated and has secondarily contaminated the word.[7] The Persian term may originally have been influenced by the Greek word.[6][8]
Intensity classifications

RSMC Tokyo's TropicalCycloneIntensityScaleCategorySustained windsViolent Typhoon≥105knots
≥194km/hVeryStrong Typhoon85–104knots
157–193km/hTyphoon64–84knots
118–156km/hSevere TropicalStorm48–63knots
89–117km/hTropical Storm34–47knots
62–88km/hTropicalDepression≤33knots
≤61km/h

A tropical depression is the lowest category that the Japan Meteorological Agency uses and is the term used for a tropical system that has wind speeds not exceeding 33 knots (38mph; 61km/h).[9] A tropical depression is upgraded to a tropical storm should its sustained wind speeds exceed 34 knots (39mph; 63km/h). Tropical storms also receive official names from RSMC Tokyo.[9] Should the storm intensify further and reach sustained wind speeds of 48 knots (55mph; 89km/h) then it will be classified as a severe tropical storm.[9] Once the system's maximum sustained winds reach wind speeds of 64 knots (74mph; 119km/h), the JMA will designate the tropical cyclone as a typhoon—the highest category on its scale.[9]
From 2009 the Hong Kong Observatory started to further divide typhoons into three different classifications: typhoon, severe typhoon and super typhoon.[10] A typhoon has wind speed of 64-79 knots (73-91mph; 118–149km/h), a severe typhoon has winds of at least 80 knots (92mph; 150km/h), and a super typhoon has winds of at least 100 knots (120mph; 190km/h).[10] The United States' Joint Typhoon Warning Center (JTWC) unofficially classifies typhoons with wind speeds of at least 130knots (67m/s; 150mph; 241km/h)—the equivalent of a strong Category4 storm in the Saffir-Simpson scale—as super typhoons.[11] However, the maximum sustained wind speed measurements that the JTWC uses are based on a 1-minute averaging period, akin to the U.S.' National Hurricane Center and Central Pacific Hurricane Center. As a result, the JTWC's wind reports are higher than JMA's measurements, as the latter are based on a 10-minute averaging interval.[12]
Genesis

There are six main requirements for tropical cyclogenesis: sufficiently warm sea surface temperatures, atmospheric instability, high humidity in the lower to middle levels of the troposphere, enough Coriolis force to develop a low pressure center, a pre-existing low level focus or disturbance, and low vertical wind shear. While these conditions are necessary for tropical cyclone formation, they do not guarantee that a tropical cyclone will form. Normally, an ocean temperature of 26.5°C (79.7°F) spanning through a depth of at least 50 metres (160ft) is considered the minimum to maintain the special mesocyclone that is the tropical cyclone. These warm waters are needed to maintain the warm core that fuels tropical systems. A minimum distance of 500km (300mi) from the equator is normally needed for tropical cyclogenesis.[13]
Whether it be a depression in the Intertropical Convergence Zone (ITCZ) or monsoon trough, a broad surface front, or an outflow boundary, a low level feature with sufficient vorticity and convergence is required to begin tropical cyclogenesis. About 85 to 90percent of Pacific typhoons form within the monsoon trough.[14] Even with perfect upper level conditions and the required atmospheric instability, the lack of a surface focus will prevent the development of organized convection and a surface low. Vertical wind shear of less than 10m/s (20kn, 33ft/s) between the ocean surface and the tropopause is required for tropical cyclone development.[13] Typically with Pacific typhoons, there are two outflow jets: one to the north ahead of an upper trough in the Westerlies, and a second towards the equator.[14]
In general, westerly wind increases associated with the Madden–Julian oscillation lead to increased tropical cyclogenesis in all tropical cyclone basins. As the oscillation propagates from west to east, it leads to an eastward march in tropical cyclogenesis with time during that hemisphere's summer season.[15] On average, twice per year twin tropical cyclones will form in the western Pacific Ocean, near the 5th parallel north and the 5th parallel south, along the same meridian, or line of longitude.[16] There is an inverse relationship between tropical cyclone activity in the western Pacific basin and the north Atlantic basin, however. When one basin is active, the other is normally quiet, and vice versa. The main reason for this appears to be the phase of the Madden–Julian oscillation, or MJO, which is normally in opposite modes between the two basins at any given time.[17]
Frequency

Nearly one-third of the world's tropical cyclones form within the western Pacific. This makes this basin the most active on Earth.[19] Pacific typhoons have formed year round, with peak months from August to October. The peak months correspond to that of the Atlantic hurricane seasons. Along with a high storm frequency, this basin also features the most globally intense storms on record. One of the most recent busy seasons was 2013. Tropical cyclones form in any month of the year across the northwest Pacific Ocean, and concentrate around June and November in the northern Indian Ocean. The area just northeast of the Philippines is the most active place on Earth for tropical cyclones to exist. Across the Philippines themselves, activity reaches a minimum in February, before increasing steadily through June, and spiking from July through October, with September being the most active month for tropical cyclones across the archipelago. Activity falls off significantly in November, although Typhoon Haiyan, the strongest Philippine typhoon on record, was a November typhoon.[20] The most frequently impacted areas of the Philippines by tropical cyclones are northern and central Luzon and eastern Visayas.[21] A ten-year average of satellite determined precipitation showed that at least 30percent of the annual rainfall in the northern Philippines could be traced to tropical cyclones, while the southern islands receive less than 10percent of their annual rainfall from tropical cyclones.[22] The genesis and intensity of typhoons are also modulated by slow variation of the sea surface temperature and circulation features following a near-10-year frequency.[23]
Paths

Most tropical cyclones form on the side of the subtropical ridge closer to the equator, then move poleward past the ridge axis before recurving north and northeast into the main belt of the Westerlies.[24] When the subtropical ridge shifts due to El Niño, so will the preferred tropical cyclone tracks. Areas west of Japan and Korea tend to experience many fewer September–November tropical cyclone impacts during El Niño and neutral years. During El Niño years, the break in the subtropical ridge tends to lie near 130°E, which would favor the Japanese archipelago.[25] During La Niña years, the formation of tropical cyclones, and the subtropical ridge position, shift westward across the western Pacific Ocean, which increases the landfall threat to China and greater intensity to Philippines.[25] Those that form near the Marshall Islands find their way to Jeju Island, Korea.[26] Typhoon paths follow three general directions.[19]
Straight track (or straight runner). A general westward path affects the Philippines, southern China, Taiwan, and Vietnam.
A parabolic recurving track. Storms recurving affect eastern Philippines, eastern China, Taiwan, Korea, Japan, and the Russian Far East.
Northward track. From point of origin, the storm follows a northerly direction, only affecting small islands.
A rare few storms, like Hurricane John, were redesignated as typhoons as they originated in the Eastern/Central Pacific and moved into the western Pacific.
Basin monitoring
Within the Western Pacific, RSMC Tokyo-Typhoon Center, part of the Japan Meteorological Agency has had the official warning responsibility for the whole of the Western Pacific since 1989,[27] and the naming responsibility for systems of tropical storm strength or greater since 2000.[10] However each National Meteorological and Hydrological Service within the western Pacific has the responsibility for issuing warnings for land areas about tropical cyclones affecting their country, such as the Joint Typhoon Warning Center for United States agencies,[28] the Philippine Atmospheric, Geophysical and Astronomical Services Administration (PAGASA) for interests in the island archipelago nation,[29] and the Hong Kong Observatory for storms that come close enough to cause the issuance of warning signals.[30]
Name sources and name list
The list of names consists of entries from 17 Southeast and East Asian nations and the United States who have territories directly affected by typhoons. The submitted names are arranged into a list, the names on the list will be used from up to down, from left to right. When all names on the list are used, it will start again from the left-top corner. When a typhoon causes damage in a country, the affected country can request for retiring the name in the next session of the ESCAP/WMO Typhoon Committee. A new name will be decided by the country whose name was retired. Unlike tropical cyclones in other parts of the world, typhoons are not named after people. Instead, they generally refer to animals, flowers, astrological signs, and a few personal names. However, Philippines(PAGASA) retains its own naming list, which does consist of human names.[31] Storms that cross the date line from the central Pacific retain their original name, but the designation of hurricane becomes typhoon. In Japan, people use the numerical designation of typhoons according to the sequence of their occurrence in the calendar year.[27]

Will Harddington
PAGASA client
Records

The most active Western Pacific typhoon season was in 1964, when 39storms of tropical storm strength formed. Only 15 seasons had 30 or more storms developing since reliable records began. The least activity seen in the northwest Pacific Ocean was during the 2010 Pacific typhoon season, when only 14tropical storms and seven typhoons formed. In the Philippines, the most active season, since 1945, for tropical cyclone strikes was 1993 when nineteen tropical cyclones moved through the country.[35] There was only one tropical cyclone that moved through the Philippines in 1958.[36] The 2004 Pacific typhoon season was the busiest for Okinawa since 1957.[37] Within Guangdong in southern China, during the past thousand years, the most active decades for typhoon strikes were the 1660s and 1670s.[38]
The highest reliably-estimated maximum sustained winds on record for a typhoon were those of Typhoon Haiyan at 195 miles per hour (314km/h) shortly before its landfall in the central Philippines on Nov. 8, 2013.[39] The most intense storm based on minimum pressure was Typhoon Tip in the northwestern Pacific Ocean in 1979, which reached a minimum pressure of 870 hectopascals (26inHg) and maximum sustained wind speeds of 165knots (85m/s, 190mph, 310km/h).[40] The deadliest typhoon of the 20th century was Typhoon Nina, which killed nearly 100,000 in China in 1975 due to a flood that caused 12 reservoirs to fail.[41] After Typhoon Morakot landed in Taiwan at midnight on August 8, 2009, almost the entire southern region of Taiwan (Chiayi County/Chiayi City, Tainan County/Tainan City (now merged as Tainan), Kaohsiung County/Kaohsiung City (now merged as Kaohsiung), and Pingtung County) and parts of Taitung County and Nantou County were flooded by record-breaking heavy rain. The rainfall in Pingtung County reached 2,327 millimeters (91.6in),[42] breaking all rainfall records of any single place in Taiwan induced by a single typhoon,[43] and making the cyclone the wettest known typhoon.
See also

China tropical cyclone rainfall climatology
Effects of tropical cyclones
Tropical cyclone
Typhoons in the Philippines
2019 Pacific typhoon season

 (in Indonesian)
 (in Thai)


The highest temperature recorded on Earth has been measured in three different major ways: air, ground, and through satellite. The former of the three is used as the standard measurement, and is noted by the World Meteorological Organization among others for the official record. How the record is taken though has been subject to controversy regarding various factors such as environmental conditions. For ninety years a former record that was measured in Libya had been in place until it was disproven in 2012. This finding has since raised questions about the legitimacy of the current record which was measured in Death Valley. The WMO has since stated that they would be willing to open an investigation into the matter as all "available evidence" points to its accuracy. While there have been higher reports through air readings, none of these have ever been verified. The other two measurements of ground and satellite have also generated higher readings, but are less reliable and also unverified.
Measurements
Air and ground temperature

The standard measuring conditions for temperature are in the air, 1.5 meters above the ground, and shielded from direct sunlight.[1] According to the World Meteorological Organization (WMO), the highest registered air temperature on Earth was 56.7°C (134.1°F) in Furnace Creek Ranch, California, located in the Death Valley desert in the United States, on July 10, 1913.[2][3][4] The validity of this record is challenged
as possible problems with the reading have since been discovered. One of these was noted as early as 1949 by Dr. Arnold Court, who came to the conclusion that the temperature may have been the result of a sandstorm that occurred at the time. Court stated that "such a storm may have caused superheated surface materials to hit upon the temperature in the shelter."[2][5] Weather historians such as Christopher C. Burt, and William Taylor Reid have also claimed that the 1913 Death Valley reading is "a myth", and is at least 4 to 5°F (2.2 to 2.8°C) too high.[6][7] If the 1913 record were to be decertified, the highest recorded air temperature on Earth would be 54.0°C (129.2°F), recorded both in Death Valley on June 20, 2013, and in Mitribah, Kuwait on July 21, 2016.[8]
These questions regarding the current record may be linked to a prevous record that had held for 90 years. From 1922 until 2012, the WMO record for the highest official temperature on Earth was 57.8°C (136.0°F), registered on September 13, 1922 in ‘Aziziya, Libya. In January 2012, the WMO decertified the 1922 record, citing persuasive evidence that it was a faulty reading recorded in error by an inexperienced observer.[2] The WMO has come out in support of the current record stating that "We accept that Death Valley temperature extreme record. Obviously if any new materials on it surface, we will be prepared to open an investigation, but at this time all available evidence points to its legitimacy."[4]
Temperatures measured directly on the ground may exceed air temperatures by 30 to 50°C.[9] The theoretical maximum possible ground surface temperature has been estimated to be between 90 and 100°C (between 194 and 212 °F) for dry, darkish soils of low thermal conductivity.[10] While there is no highest confirmed ground temperature, a reading of 93.9°C (201°F) was allegedly recorded in Furnace Creek Ranch on July 15, 1972.[11]
Satellite measurements
Temperature measurements via satellite also tend to capture occurrence of higher records but, due to complications involving satellite's altitude loss (a side effect of atmospheric friction), these measurements are often considered less reliable than ground-positioned thermometers.[12] The highest recorded temperature taken by a satellite is 66.8°C (152.2°F), which was measured in the Flaming Mountains of China in 2008.[13] Other satellite measurements of ground temperature taken between 2003 and 2009, taken with the MODIS infrared spectroradiometer on the Aqua satellite, found a maximum temperature of 70.7°C (159.3°F), which was recorded in 2005 in the Lut Desert, Iran. The Lut Desert was also found to have the highest maximum temperature in 5 of the 7 years measured (2004, 2005, 2006, 2007 and 2009). These measurements reflect averages over a large region and so are lower than the maximum point surface temperature.[9]
Unverified claims
The following are unverified claims of extreme heat over the current world record of 56.7°C (134.1°F). These include historical claims that were never authenticated due to the equipment available at the time, and unverified scientific claims. Amateur readings have also been done through social media that claimed extreme temperatures which were later discredited. Videos were posted in one instance that allegedly showed street lights melting or trees bursting into flames. These were later disproven by meteorologists who tied the "evidence" to other unrelated prior events that took place.[14]

See also
Desert climate
Highest temperatures ever recorded
Lowest temperature recorded on Earth
Lowest temperatures ever recorded
Orders of magnitude (temperature)

How many degrees has the earth's temperature raised?


The history of chocolate begins in Mesoamerica. Fermented beverages made from chocolate date back to 350 BC.[1] The Aztecs believed that cacao seeds were the gift of Quetzalcoatl, the god of wisdom, and the seeds once had so much value that they were used as a form of currency. Originally prepared only as a drink, chocolate was served as a bitter, from a liquid, mixed with spices or corn puree. It was believed to have aphrodisiac powers and to give the drinker strength. Today, such drinks are also known as "Chilate" and are made by locals in the South of Mexico.
After its arrival to Europe in the sixteenth century, sugar was added to it and it became popular throughout society, first among the ruling classes and then among the common people. In the 20th century, chocolate was considered essential in the rations of United States soldiers at war.[2]
The word "chocolate" comes from the Classical Nahuatl word chocolātl, and entered the English language from the Spanish language.[3]
History
Cultivation, consumption, and cultural use of cacao were extensive in Mesoamerica where the cacao tree is native.[4] When pollinated, the seed of the cacao tree eventually forms a kind of sheath, or ear, 20" long, hanging from the tree trunk itself. Within the sheath are 30 to 40 brownish-red almond-shaped beans embedded in a sweet viscous pulp. While the beans themselves are bitter due to the alkaloids within them, the sweet pulp may have been the first element consumed by humans.
Cacao pods themselves can range in a wide range of colors, from pale yellow to bright green, all the way to dark purple or crimson. The skin can also vary greatly - some are sculpted with craters or warts, while others are completely smooth. This wide range in type of pods is unique to cacaos in that their color and texture does not necessarily determine the ripeness or taste of the beans inside.[5]
Evidence suggests that it may have been fermented and served as an alcoholic beverage as early as 1400 BC.[6]
Cultivation of the Cacao was not an easy process. Part of the reason was that was due to the fact that, Cacao trees in their natural environment grew up to 60 or more feet tall. When the trees were grown in a plantation however, they grew to around 20 feet tall.
While researchers do not agree which Mesoamerican culture first domesticated the cacao tree, the use of the fermented bean in a drink seems to have arisen in North America (Mesoamerica—Central America and Mexico). Scientists have been able to confirm its presence in vessels around the world by evaluating the "chemical footprint" detectable in the microsamples of contents that remain.[1] Ceramic vessel with residues from the preparation of chocolate beverages have been found at archaeological sites dating back to the Early Formative (1900–900 BC) period.  For example, one such vessel found at an Olmec archaeological site on the Gulf Coast of Veracruz, Mexico dates chocolate's preparation by pre-Olmec peoples as early as 1750 BC.[7]  On the Pacific coast of Chiapas, Mexico, a Mokayanan archaeological site provides evidence of cacao beverages dating even earlier, to 1900 BC.[7]
Pueblo people, who lived in an area that is now the U.S. Southwest, imported cacao from Mesoamerican cultures in southern Mexico or Central America between 900 and 1400.  They used it in a common beverage consumed by everyone in their society.[1]
Archaeological Evidence of Cacao in Mesoamerica
Nature Ecology & Evolution reported probably the earliest cacao use from approximately 5,300 years ago recovered from the Santa Ana (La Florida) site in southeast Ecuador.[8]
Another find of chemically traced cacao was in 1984, when a team of archaeologists in Guatemala explored the Mayan site of Rio Azul. They discovered fifteen vessels surrounding male skeletons in the royal tomb. One of these such vessels was beautifully decorated and covered in various Mayan glyphs. One of these glyphs translated to "kakaw", also known as cacao. The inside of the vessel was lined with a dark colored powder, which was scraped off for further testing. Once the archaeologists took this powder to the Hershey Center for Health and Nutrition to be tested, they found trace amounts of theobromine in the powder, a major indicator of cacao. This cacao was dated to sometime between 460 and 480 AD [9]
Cacao powder was also found in beautifully decorated bowls and jars, known as tecomates, in the city of Puerto Escondido. Once thought to have been a very rare commodity, cacao was found in many more tecomates than once thought possible. However, since this powder was only found in bowls of higher quality, it led archaeologists to believe that only wealthier people could afford such bowls, and therefore the cacao. The cacao tecomates are thought to have been a center piece to social gatherings between people of high social status.[9]
Olmec Use
Earliest evidence of domestication of the cacao plant dates to the Olmec culture from the Preclassic period.[10] The Olmecs used it for religious rituals or as a medicinal drink, with no recipes for personal use. Little evidence remains of how the beverage was processed.
Mayan Use
The Maya people, (Guatemala), by contrast, do leave some surviving writings about cacao which confirm the identification of the drink with the gods. The Dresden Codex specifies that it is the food of the rain deity Kon, the Madrid Codex that gods shed their blood on the cacao pods as part of its production.[11] The Maya people gathered once a year to give thanks to the god Ek Chuah who they saw as the Cacao god.[12] The consumption of the chocolate drink is also depicted on pre-Hispanic vases. The Maya seasoned their chocolate by mixing the roasted cacao seed paste into a drink with water, chile peppers and cornmeal, transferring the mixture repeatedly between pots until the top was covered with a thick foam.[2]
There were many uses for cacao among the Maya. It was used in official ceremonies and religious rituals, at feasts and festivals, as funerary offerings, as tribute, and for medicinal purposes. Both cacao itself and vessels and instruments used for the preparation and serving of cacao were used for important gifts and tribute.[13] Cacao beans were used as currency, to buy anything from avocados to turkeys to sex. A rabbit, for example, was worth ten cacao beans, (called “almonds” by the early sixteenth-century chronicler Francisco Oviedo y Valdés), a slave about a hundred, and the services of a prostitute, eight to ten “according to how they agree,”.[14] The beans were also used in betrothal and marriage ceremonies among the Maya, especially among the upper classes.
“The form of the marriage is: the bride gives the bridegroom a small stool painted in colors, and also gives him five grains of cacao, and says to him “These I give thee as a sign that I accept thee as my husband.” And he also gives her some new skirts and another five grains of cacao, saying the same thing.”[15]
Mayan preparation of cacao started with cutting open cacao pods to expose the beans and the fleshy pulp. The beans were left out to ferment for a few days. In some cases, the beans were also roasted over an open fire in order to add a smoky flavor to it. The beans then had their husks removed and were ground into a paste. Since sweeteners were rarely used by Mayans, they flavored their cacao paste with additives like flowers, vanilla pods, and chilies. The vessel used to serve this chocolate liquid was stubbier by nature to help froth the liquid better, which was very important to the Mayans. The vessels also tended to be decorated in intricate designs and patterns, which tended to only be accessible by the rich.[10]
Aztec Use
By 1400, the Aztec Empire took over a sizable part of Mesoamerica. They were not able to grow cacao themselves, but were forced to import it.[2] All of the areas that were conquered by the Aztecs that grew cacao beans were ordered to pay them as a tax, or as the Aztecs called it, a "tribute". The cacao bean became a form of currency. The Spanish conquistadors left records of the value of the cacao bean, noting for instance that 100 beans could purchase a canoe filled with fresh water or a turkey hen.[6][16] The Aztecs associated cacao with the god Quetzacoatl, whom they believed had been condemned by the other gods for sharing chocolate with humans.[2] Unlike the Maya of Yucatán, the Aztecs drank chocolate cold. It was consumed for a variety of purposes, as an aphrodisiac or as a treat for men after banquets, and it was also included in the rations of Aztec soldiers.[17]
History in Europe

Early history
Until the 16th century, the cacao tree was wholly unknown to Europeans.[2]
Christopher Columbus encountered the cacao bean on his fourth mission to the Americas on August 15, 1502, when he and his crew seized a large native canoe that proved to contain among other goods for trade, cacao beans.[18] His son Ferdinand commented that the natives greatly valued the beans, which he termed almonds, "for when they were brought on board ship together with their goods, I observed that when any of these almonds fell, they all stooped to pick it up, as if an eye had fallen."[18] But while Columbus took cacao beans with him back to Spain,[18] it made no impact until Spanish friars introduced chocolate to the Spanish court.[2]

Spanish conquistador Hernán Cortés may have been the first European to encounter chocolate when he observed it in the court of Montezuma in 1519.[19]  In 1568, Bernal Diaz, who accompanied Cortés in the conquest of Mexico, wrote of this encounter which he witnessed:
From time to time they served him [Montezuma] in cups of pure gold a certain drink made from cacao.  It was said that it gave one power over women, but this I never saw.  I did see them bring in more than fifty large pitchers of cacao with froth in it, and he drank some of it, the women serving with great reverence.[20]
Jose de Acosta, a Spanish Jesuit missionary who lived in Peru and then Mexico in the later 16th century, described its use more generally:
Loathsome to such as are not acquainted with it, having a scum or froth that is very unpleasant taste. Yet it is a drink very much esteemed among the Indians, where with they feast noble men who pass through their country. The Spaniards, both men and women that are accustomed to the country are very greedy of this Chocolate. They say they make diverse sorts of it, some hot, some cold, and some temperate, and put therein much of that "chili"; yea, they make paste thereof, the which they say is good for the stomach and against the catarrh.
After the Spanish conquest of the Aztecs, chocolate was imported to Europe. At the beginning Spaniards would use it as a medicine to treat illnesses such as abdominal pain because it had a bitterness to it. Once sweetened, it transformed.[21] It quickly became a court favorite. It was still served as a beverage, but the addition of sugar or honey counteracted the natural bitterness.[6] The Spaniards initially intended to recreate the original taste of the Mesoamerican chocolate by adding similar spices, but this habit had faded away by the end of the eighteenth century.[22] Within about a hundred years, chocolate established a foothold throughout Europe.[2]
How the word "chocolate" came into Spanish is not certain.  The authority on the Spanish language, the Royal Spanish Academy, derives it from the  Nahuatl word "xocolatl" (pronounced Nahuatl pronunciation:[ ʃoˈkolaːtɬ]) made up from the words "xococ" meaning sour or bitter, and "atl" meaning water or drink.[23]  However, as William Bright noted[24] the word "chocolatl" doesn't occur in central Mexican colonial sources making this an unlikely derivation.  Santamaria[25] gives a derivation from the Yucatec Maya word "chokol" meaning hot, and the Nahuatl "atl" meaning water.  More recently Dakin and Wichman derive it from another Nahuatl term, "chicolatl" from Eastern Nahuatl meaning "beaten drink".[26]  They derive this term from the word for the frothing stick, "chicoli". The word xocoatl means beverage of the maize.[27] The words "cacaua atl" mean drink of cacao.[27] The word "xocolatl" does not appear in Molina's dictionary, Vocabulario en Lengua Castellana y Mexicana y Mexicana y Castellana.[27]
Expansion

The new craze for chocolate brought with it a thriving slave market, as between the early 17th and late 19th centuries the laborious and slow processing of the cacao bean was manual.[2] Cacao plantations spread, as the English, Dutch, and French colonized and planted. With the depletion of Mesoamerican workers, largely to disease, cacao production was often the work of poor wage laborers and African slaves. Wind-powered and horse-drawn mills were used to speed production, augmenting human labor. Heating the working areas of the table-mill, an innovation that emerged in France in 1732, also assisted in extraction.[28]
The Chocolaterie Lombart, created in 1760, claimed to be the first chocolate company in France, ten years before Pelletier et Pelletier.[29]
New processes that speed the production of chocolate emerged early in the Industrial Revolution. In 1815, Dutch chemist Coenraad van Houten introduced alkaline salts to chocolate, which reduced its bitterness.[2] A few years thereafter, in 1828, he created a press to remove about half the natural fat (cacao butter) from chocolate liquor, which made chocolate both cheaper to produce and more consistent in quality. This innovation introduced the modern era of chocolate.[18] Known as "Dutch cocoa", this machine-pressed chocolate was instrumental in the transformation of chocolate to its solid form when in 1847 Joseph Fry learned to make chocolate moldable by adding back melted cacao butter.[6] Milk had sometimes been used as an addition to chocolate beverages since the mid-17th century, but in 1875 Daniel Peter invented milk chocolate by mixing a powdered milk developed by Henri Nestlé with the liquor.[2][18] In 1879, the texture and taste of chocolate was further improved when Rodolphe Lindt invented the conching machine.[30]
Lindt & Sprüngli AG, a Swiss-based concern with global reach, had its start in 1845 as the Sprüngli  family confectionery shop in Zurich that added a solid-chocolate factory the same year the process for making solid chocolate was developed and later bought  Lindt's factory. Besides Nestlé, several chocolate companies had their start in the late 19th and early 20th centuries.  Cadbury was manufacturing boxed chocolates in England by 1868.[2] In 1893, Milton S. Hershey purchased chocolate processing equipment at the World's Columbian Exposition in Chicago and soon began the career of Hershey's chocolates with chocolate-coated caramels.
Although it was men leading the charge towards mass production of chocolate for everyday people, advertisements targeted women, who “were charged with providing wholesome cocoa for respectable consumption within the family,”.[31] Women were also targeted by advertising campaigns within courtship rituals,[31] though most early advertising was aimed more at housewives and mothers than at single women.
Modern use

Roughly two-thirds of the world's cocoa is produced in Western Africa, with Ivory Coast being the largest source, producing a total crop of 1,448,992 tonnes.[32] Ghana, Nigeria, and Cameroon are other West African countries among the top 5 cocoa producing countries in the world. Like many food industry producers, individual cocoa farmers are at the mercy of volatile world markets. The price can vary from between £500 ($945) and £3,000 ($5,672) per ton in the space of just a few years.  While investors trading in cocoa can dump shares at will, individual cocoa farmers can not ramp up production and abandon trees at anywhere near that pace.
Only three to four percent of "cocoa futures" contracts traded in the cocoa markets ever end up in the physical delivery of cocoa. Every year seven to nine times more cocoa is bought and sold on the exchange than exists.
See also

Alonso de Molina's dictionary of 1571 and of 1555
Food history
History of yerba mate
List of English words of Nahuatl origin

When was chocolate first brought to Europe?