St. Sophia Church was built during the reign of Emperor Theodosius and burned down in the fire of Nika Revolt in 532 A.D. during the reign of Justinian. The same year Justinian ordered to build a new basilica, the one we can see today, and only five years later, 537 AD, it was opened to the public. The architects of this new basilica were Isidorus from Miletus (Söke) and Anthemious from Tralles (Aydın). The basilica was covered with the magnificient dome 55.60 m high and 30.80 - 31.88 m in diameter, with 40 frame timbers and 107 pillars.
In 1453, with the conquest of Istanbul, Sultan Mehmed the Conqueror converted the church into a mosque. To strengthen the building architect Sinan did significant work in Hagia Sophia in the Turkish period. During the reign of Sultan Abdulmecid (1839 - 1861) the Fossati brothers made various restorations in the building. Hagia Sophia Museum, the legacy of both Christian and Muslim cultures, was opened for visits according to the order of Atatürk and decision of the Turkish Assembly of Ministers on the 1st of February, 1935.
The Hagia Sophia Museum was included in the list of World Heritage of UNESCO .