Following Emperor Theodosius’ decision to ban all pagan rituals, the first Christian churches were built in the 5th century while the Decree of the Emperor Justinian (529) prohibiting the operation of the philosophical schools, effectively sealed the fate of Athens as a scholarly centre. From the 6th century onward, Athens suffered from continuous raids, which left the city in ruins.
However, Athens was never deserted and during the first Byzantine period the new religion established firm roots in the city. Athens became ‘Episcopal See’ in 733 and most of its temples were converted to churches, including the Parthenon which became a well-known pilgrimage, dedicated to the Virgin Mary, called Panagia Athiniotissa.
The grandest Byzantine churches and monuments in and around Athens were built during the 11th and 12th century, reflecting another period of development this time as a provincial city of the Empire. In 1204, the Fourth Crusade conquered Athens and set up the Duchy of Athens, which for the next two and a half centuries, would be passed through the hands of Catalans, Florentines and Venetians who plundered the monuments. The western side of the Acropolis, where the Propylaea are, was fortified with bastions and was converted into a palace for the governor. The Erechtheion became the guard’s headquarters and the Parthenon a catholic church dedicated to Notre Dame.
In 1458, Athens fell peacefully to the Ottoman Turks, who granted the city certain privileges including keeping the Christian churches; except for the Parthenon, which was converted to a mosque.
During an unfortunate episode of the Great Turkish Wars, a long held conflict between the Ottomans and the Venetians, in September 1687, Venetian army leader Morosini took a direct shot at the Acropolis with cannons, causing the gaping hole visible today in the Parthenon. The Acropolis was once more the theatre of war during the Greek War of Independence, in the 19th century, causing further damage to the monuments. In early 19th century, Lord Elgin who was ambassador to the Ottoman Empire has plundered the Parthenon sculptures hacking them from the temple and then selling them to the British Museum.
Ottoman Athens’ economic, cultural, social and commercial centre was organized around the Library of Hadrian and was a real mosaic of cultures and religions but few monuments from the period remain today. The last remaining Ottoman soldiers left the city on March 1833 and Athens was returned to Greek hands after many centuries.