Hagia Sophia officially the Great Mosque of Ayasofya is a Late Antique place of worship in Istanbul’s capital district of Fatih that has served as a Greek Orthodox Christian patriarchal cathedral, briefly a Roman Catholic cathedral, later an Ottoman mosque, a museum and currently a mosque once again.
Built as the Christian cathedral of Constantinople between 532 and 537 on the orders of Justinian I, the basilica was designed by the Greek geometers Isidore of Miletus and Anthemius of Tralles. The present Justinianic building was the third church of the same name to occupy the site, the prior one having been destroyed in the Nika riots. Being the Episcopal see of the ecumenical patriarch of Constantinople, it remained the world’s largest cathedral for nearly a thousand years.
After the Fall of Constantinople to the Ottoman Empire in 1453, it was converted to a mosque. In 1935, the first Turkish President and founder of the Republic of Turkey, Mustafa Kemal Atatürk, transformed the building into a museum.
Hagia Sophia is currently (2014) the second most visited museum in Turkey, attracting almost 3.3 million visitors annually.
In early July 2020, the Council of State annulled the Cabinet’s 1934 decision to establish the museum, revoking the monument’s status and a subsequent decree of the President of Turkey ordered the reclassification of Hagia Sophia as a mosque, a controversial move that has invoked condemnation from the World Council of Churches and many international leaders.
When President Erdogan announced that the first Muslim prayers would be held inside the building on 24 July, he added that “like all our mosques, the doors of Hagia Sophia will be wide open to locals and foreigners, Muslims and non-Muslims.” UNESCO announced it “deeply regrets” the conversion, “made without prior discussion”, and asked Turkey to “open a dialogue without delay”, stating that the lack of negotiation was “regrettable”.