Hagia Sophia is a former Orthodox patriarchal basilica, later a mosque, and now a museum in Istanbul, Turkey. From the date of its dedication in 360 until 1453, it served as the cathedral of Constantinople, except between 1204 and 1261, when it was converted to a Roman Catholic cathedral under the Latin Patriarch of Constantinople of the Western Crusader established Latin Empire. The building was a mosque from 29 May 1453 until 1931, when it was secularized. It was opened as a museum on 1 February 1935.
Hagia Sophia is a great architectural beauty and an important monument both for Byzantine and for Ottoman Empires. Once a church, later a mosque, and now a museum at the Turkish Republic, Hagia Sophia has always been the precious of its time.
The mystical city Istanbul hosted many civilizations since centuries, of which Byzantium and Ottoman Empires were both the most famous ones. The city today carries the characteristics of these two different cultures and surely Hagia Sophia is a perfect synthesis where one can observe both Ottoman and Byzantium effects under one great dome.
The Hagia Sophia or Ayasofya as it is known in Turkish was actually a patriarchal Basilica that has been considered to be an embodiment of Byzantine architecture and also had the distinction of remaining the largest cathedral in the world until 1520. Built on the orders of the Byzantine Emperor Justinian, its interiors were richly decorated with artistic mosaics depicting various religious scenes and were supported by massive marble pillars.
The Byzantine Church of Hagia Sophia stands atop the first hill of Constantinople at the tip of the historic peninsula, surrounded by the waters of the Sea of Marmara, the Bosphorus and the Golden Horn on three sides. It was built by Justinian I between 532 and 537 and is located in close proximity to the Great Palace of the Emperors, the Hippodrome, and the Church of Hagia Irene. The third known church to be built at its site since 360, the Justinian church replaced the smaller basilica built by Theodosius II in 415, which burnt down in the Nika riots against Justinian I and Empress Theodora. Beginning construction immediately after suppressing the revolt, Justinian commissioned physicist Isidoros of Miletus, and mathematician Anthemios of Thrales (today’s Aydin) to build a church larger and more permanent than its precedents to unify the church and reassert his authority as the emperor. There is little that remains from the earlier churches beside the baptistery and the skeuophylakion. The skeuophylakion, a round building that houses the patriarchal treasure, is located off the east corner and the baptistery, which was converted into an Ottoman tomb in 1639, stands to the southwest.
The grand dome of the Hagia Sophia, an impressive technical feat for its time, is often thought to symbolize the infinity of the cosmos signified by the Holy Soul to which the church was dedicated. It took five years to reconstruct the dome after it collapsed in an earthquake in 557. The new dome, which is taller and braced with forty ribs, was partially rebuilt after damage in the 859 and 989 earthquakes. Plundered during the Latin invasion following the Forth Crusade in 1204, the church was restored under Andronicos II during Palaeologan rule. The great southeast arch was reconstructed after the 1344 earthquake. As the Cathedral of the Ecumenical Patriarchate of Constantinople for over a thousand years, with the brief exception of the Latin occupation, the Hagia Sophia was the center of Eastern Christianity from 360 to the Ottoman conversion. Its importance as the center of religious authority in the Byzantine capital was compounded with its role as the primary setting for state rituals and pageantry. The Ottoman conquest of Constantinople in 1453, which put an end to the Byzantine Empire, began the era of Islamic worship in the holy structure, which Mehmed II converted into a mosque immediately after his conquest.
Known then on as the Ayasofya Mosque, the Hagia Sophia remained the Great Mosque of the Ottoman capital until its secularization under the Turkish Republic In 1934. Little was modified during the initial conversion when a mihrab, a minber and a wooden minaret were added to the structure. Mehmed II built a madrasa near the mosque and organized a waqf for its expenses. Extensive restorations were conducted by Mimar Sinan during the rule of Selim II; the original sultan’s lodge was added at this time. Mimar Sinan built the Tomb of Selim II to the southeast of the mosque in 1577 and the tombs of Murad III and Mehmed III were built next to it in the 1600s. Mahmud I, who ordered a restoration of the mosque in 1739, added an ablution fountain, Koranic school, soup kitchen and library, making the mosque the center of a social complex. Perhaps the most well known restoration of the Hagia Sophia was completed between 1847-49 during the rule of Abdülmecid II, who invited Swiss architects Gaspare and Guiseppe Fossati to renovate the building. In addition to consolidating the dome and vaults and straightening columns, the two architects brothers revised the decoration of the exterior and the interior. The discovery of the figural mosaics after the secularization of Hagia Sophia, was guided by the descriptions of the Fossati brothers who uncovered them a century earlier for cleaning and recording. An earlier record of the Hagia Sophia mosaics is found in the travel sketches of Swedish engineer Cornelius Loos from 1710-1711.
The period of systematic study, restoration and cleaning of Hagia Sophia, initiated by the Byzantine Institute of the United States and the Dumbarton Oaks Field Committee in the 1940s, still continues to our day. Archaeological research led by K. J. Conant, W. Emerson, R. L. Van Nice, P.A. Underwood, T. Whittemore, E. Hawkins, R. J. Mainstone and C. Mango have illuminated different aspects related to the history, structure and decoration of the Justinian church. A. M. Schneider and F. Dirimtekin after him have excavated remains of the earlier churches outside the Justinian church. A colloquium convened at Princeton University in 1989 has led the way towards a computer-based structural modeling of the church directed by Prof. A. Çakmak. This work has provided the basis for a new restoration project underway since 1995 that focuses on structural monitoring to gauge long-term stability of the structure along with historical restoration. The Hagia Sophia was included in the annual list of 100 most endangered monuments published by the World Monuments Fund in 1996 and in 1998, to secure funds for continued work. Considered a significant influence on the conception of classical Ottoman architecture, the Hagia Sophia is open to visitors as a public museum.
A 1993 UNESCO mission to Turkey noted falling plaster, dirty marble facings, broken windows, decorative paintings damaged by moisture, and ill-maintained lead roofing. Cleaning, roofing and restoration have since been undertaken; many recent visitors have found their view obstructed by a huge scaffolding stretching up into the dome in the center of the nave.