After Constantinople was conquered by the Franks of the 4th Crusade in 1204, Athens passed in the hands of Boniface of Montferrat who gave it, along with the town and the area of Megara, to Otto de La Roche of Bourgogne who also dominated the area of Thiva in Boeotia. Otto organized Attica in the model of the feudal regions of Western Europe. Otto was succeeded by his nephew, Guy 1st, who was nominated Duke by the French king Louis IX. After this, a Catholic archbishop was appointed in Athens in the place of the Orthodox bishop Michael Honiatis who decided to exile himself at the island of Kea; the Latin archbishop was approved by the local clergymen. The political and church authorities of the city had their seat on the Acropolis which the dominants strengthened by fortifying it with walls; the new walls made the place looking like a medieval castle. It is in this period that there was constructed the so-called Fragikos Pyrgos (“the Frankish Tower”), a tall tower surveying the entire basin. The tower stood there until the mid-19th century, when it was pulled down.
In this period of time Athens was inhabited only in the interior of the so-called Late Roman wall, below the Acropolis, at the North. In mid 13th century it was constructed a low surrounding wall, protecting the Acropolis, which ever since took the name of Rizokastro. The residence of the Duke of Athens was at Propylaea, the Latin archbishop lived in the Erectheion, while the Parthenon, already converted to the orthodox church of Panaghia Atheniotissa since the period of king Justinian, became now a Catholic church.
The first period of Frankish domination was a peaceful one; thanks to the activities of Venetian and Genovese tradesmen, the economy of the area was developing well enough and Thiva became the center of the economic activity, as a great production of silk had been established there. There were also several art workshops which produced many kinds of artifacts in western style, mainly in the style of Bourgogne.
The years of peace and prosperity came to an end in 1311 when the mercenaries of the Catalan society took possession of the city of Athens and of the rest of the Duchy and assigned authority to the king of Aragon. The Catalan language had then become the official language of the Duchy; the Catholic archbishop transferred his seat at Thiva and the legislation of Barcelona was adopted, which interdicted the people of Athens to pursue most of the professions. As a result, during the 80 years of the Catalan domination, Athens declined and the economic activity slacked.
In 1387 the Florentines under the command of Nerio Acciaiuoli occupied Athens, the Acropolis and the area around and kept it almost continuously but for a short period when the place passed in the hands of the Venetians, until 1458, when the Ottomans took possession of it. Acciaiuoli transferred the seat of his state anew in Athens and initiated several works for the development and embellishment of the city, which flourished again. It is during this period that the port of Piraeus was repaired; the Parthenon, still a Catholic church, the so-called Santa Maria de Setines was renovated and many roads were constructed or restored, which contributed very much to the development of trade. In order to gain the favor of the locals, the Florentine lord of Athens allowed the use of the Greek language and the appointment of an Orthodox bishop. Thanks to these modifications, several Athenian families achieved to flourish economically and socially; one of the most well known among them was the family of Chalcocondyles. According to scholars, it is in the same period that “Arvanites” established in Attica and Boeotia. Arvanites were an Albanian-speaking population who were Orthodox.
The flourish of the city has much to do with the renaissance of Letters and Arts that had already started in the Italian cities as Florence. The affection of the Florentines for ancient literature was also proved by works made in Athens. The Florentines could not forget that Athens was the cultural and intellectual center of classical antiquity. Also, in the same period many travelers from Europe visited Athens. The years of flourish lasted until 1456 when Mehmet the Conqueror occupied the area of Athens and the Acropolis two years later, in 1458.