Constantinople, or Byzantium (today Istanbul), was dedicated by Constantine the Great as his capital in 330 AD and functioned as the glorious center of the Byzantine Empire (the eastern portion of the Roman Empire) for centuries thereafter.
By 1400, however, the city was in serious decline. Byzantine power had eroded over the years and many of the best and the brightest had deserted for more prosperous and alluring places. The emerging Muslim Ottoman Empire, with its roots in Anatolia, had grown and prospered while Christian Constantinople decayed. In 1452, Sultan Mehmed II (sometimes Muhammad II) began preparations for conquering the city. He constructed a fortress at the narrow point of the Bosporus, assembled a large and experienced army and arranged the neutrality of Hungary and Venice (likely allies of the Byzantines). A 54-day siege began in April 1453. The walled city was bombarded almost constantly from Ottoman cannons on both land and sea. The walls were breached on May 29; Emperor Constantine XI died amidst his Genoese supporters and fellow townspeople. Two days of looting, murder and rape followed before order was restored by the sultan, soon to be known as Mehmed the Conqueror.
The fall of Constantinople has long been regarded as a watershed event in world history. Indeed, it was to the vanquished Christian inhabitants of the city, as well as to the victorious Ottomans, who restored the metropolis to its former glory. Nevertheless, some claims about this event have not withstood careful scrutiny.
Some authorities have maintained that the destruction of the last vestige of the Byzantine Empire marked an abrupt end to the Middle Ages and the dawn of a new era. However, a Renaissance was already flowering in Italy in 1453 and medieval ways would persist in northern Europe for many more years. These trends would have continued with or without the fall of Constantinople.
Many histories, including some of recent vintage, cite the fall of Constantinople as a spur to the Age of Discovery. It is argued that the triumphant Ottomans denied Christian merchants access through the Black Sea to the lucrative trade routes to the East. With that entry denied, Western Europe was forced to seek new avenues. In fact, advances in shipbuilding technology, navigation methods and the accumulation of capital sufficient to support exploratory ventures predated the Ottoman triumph and account for the burst of European energy.