Hagia Sophia 🇹🇷

Hagia Sophia, officially known as the Hagia Sophia Grand Mosque, is a major historical complex and architectural landmark situated in Istanbul, Turkey. Originally constructed as an Eastern Orthodox cathedral, the monument has undergone several functional transitions over the centuries, serving as a church, a Roman Catholic cathedral, a museum, and an active mosque. Renowned as a quintessential example of Byzantine architecture, the building is notable for its expansive interior space and its pioneering use of a fully pendentive dome.

The present structure was commissioned by the Byzantine Emperor Justinian I and constructed between 532 and 537 under the supervision of the Greek geometers Isidore of Miletus and Anthemius of Tralles. It stands on the site of two earlier religious buildings: a 4th-century church consecrated during the reign of Constantius II that was destroyed by fire in 404, and a 5th-century basilica inaugurated under Theodosius II that was burned down during the Nika Revolt in 532. Following its completion, Justinian's basilica remained the largest church in the world for more than five hundred years, serving as the spiritual center of the Eastern Orthodox Church and setting an architectural template for subsequent religious buildings.

Throughout its history, the site was the backdrop for key historic developments. In 1054, the delivery of an excommunication decree inside the sanctuary marked the beginning of the East–West Schism. During the Fourth Crusade in 1204, the complex was converted into a Catholic cathedral, during which time the Venetian Doge Enrico Dandolo was buried within the church, before Orthodox control was restored in 1261. Following the fall of Constantinople in 1453, Sultan Mehmed the Conqueror converted the structure into a mosque, introducing minarets to the exterior.

In 1935, under the secular Republic of Turkey, the complex was reopened as a museum, eventually becoming the most visited tourist attraction in the country. The site was reclassified back into a mosque in 2020. Visitors to the precinct can observe elements reflecting its complex structural past, including excavated stone foundations, carved column fragments, and decorative friezes from the 5th-century basilica uncovered near the western entrance, as well as an adjacent circular brick treasury building known as the skeuophylakion.