Hagia Sophia

Hagia Sophia, whose Greek name means “Holy Wisdom,” stands in Istanbul, formerly Constantinople. The present building was constructed between 532 and 537 under Byzantine emperor Justinian I, after an earlier church on the site was destroyed during the Nika revolt. Architects Anthemius of Tralles and Isidore of Miletus designed the structure. For centuries it served as the principal church of the Byzantine capital and a major center of religious and civic life.

The building combines a longitudinal basilica plan with a domed central space. Its great dome, carried on pendentives and flanked by semi-domes, creates a broad interior that was unusual for its time. Earthquakes damaged the structure, including a partial collapse of the dome in the sixth century, followed by reconstruction and later reinforcement. Marble surfaces, columns and surviving mosaics form part of its layered interior; some Christian imagery has at different times been concealed or uncovered as the building's function and caretaking changed.

After the Ottoman conquest of Constantinople in 1453, Sultan Mehmed II converted the church into a mosque. Over time, minarets and other Islamic architectural elements were added, and the building influenced Ottoman mosque design. In 1934 the Turkish Republic decided to establish it as a museum, which opened in 1935. In 2020 it returned to mosque status. These changes did not erase earlier layers: the building's architecture and decoration record successive communities and uses.

Hagia Sophia is a component of UNESCO's Historic Areas of Istanbul World Heritage property. UNESCO describes it as a major sixth-century monument within a city shaped by Byzantine and Ottoman political, religious and artistic histories. Its scale, engineering and long sequence of adaptations have made it influential in the histories of both churches and mosques. It is also a living religious site, so its conservation and contemporary use have drawn international attention and discussion.