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.