Hagia Sophia | History, Architecture, Mosaics, Facts, & Significance

History

The original church on the site of the Hagia Sophia is said to have been ordered to be built by Constantine I in 325 on the foundations of an ancient temple. Constantine’s son, Constantius II, consecrated the church, called the Magna Ecclesia (“Great Church”), in 360. It was damaged in 404 by a fire that erupted during a public disturbance following the second banishment of St. John Chrysostom, then patriarch (archbishop) of Constantinople. It was subsequently rebuilt and enlarged by the Roman emperor Constans I. The restored building was rededicated in 415 by Theodosius II. The church stood for more than a century when it was burned again in the Nika insurrection of January 532, a circumstance that gave the then emperor Justinian I an opportunity to envision a splendid replacement.

The resultant Hagia Sophia was built in the remarkably short time of about six years, being completed in 537 ce. Unusual for the period in which it was built, the names of the building’s architects—Anthemius of Tralles and Isidorus of Miletus—are well known, as is their familiarity with mechanics and mathematics. The structure now standing is essentially the 6th-century edifice, although an earthquake caused a partial collapse of the dome in 558 (restored 562) and there were two further partial collapses, after which it was rebuilt to a smaller scale and the whole church reinforced from the outside. It was restored again in the mid-14th century. For more than a millennium it was the Cathedral of the Ecumenical Patriarchate of Constantinople. In 1204 the church was looted during the sack of Constantinople by the Crusaders on the Fourth Crusade.

After the Turkish conquest of Constantinople in 1453, Mehmed II had it repurposed as a mosque, with the addition of a wooden minaret (on the exterior, a tower used for the summons to prayer), a great chandelier, a mihrab (niche indicating the direction of Mecca), and a minbar (pulpit). Either he or his son Bayezid II erected the red minaret that stands on the southeast corner of the structure. The original wooden minaret did not survive. Bayezid II erected the narrow white minaret on the northeast side of the mosque. The two identical minarets on the western side were likely commissioned by Selim II or Murad III and built by renowned Ottoman architect Sinan in the 1500s.

Turkish: Ayasofya (Show more) Latin: Sancta Sophia (Show more) Also called: Church of the Holy Wisdom or Church of the Divine Wisdom (Show more) In full: Hagia Sophia Grand Mosque (Show more) On the Web: CNN Travel - Hagia Sophia: Secrets of the 1,600-year-old megastructure that has survived the collapse of empires (Jan. 19, 2026) (Show more) See all related content

In 1934 Turkish Pres. Kemal Atatürk secularized the building, and in 1935 it was made into a museum. In 1985 the Hagia Sophia was designated a component of a UNESCO World Heritage site called the Historic Areas of Istanbul, which includes that city’s other major historic buildings and locations. Pres. Recep Tayyip Erdoğan made the controversial decision in 2020 to convert the building back into a mosque. Islamic prayers were held shortly after the announcement with curtains partially concealing the building’s Christian imagery. As Turkey’s most popular tourist destination, the Hagia Sophia remained open to visitors.