Hagia Sophia Architecture Guide: A History of the Hagia Sophia

The Hagia Sophia is a historic place of worship in Istanbul, Turkey, in Eastern Europe. The Hagia Sophia has many names: “Ayasofya” in Turkish, “Sancta Sophia” in Latin, and “Holy Wisdom” or “Divine Wisdom” in English. The current structure was built in the sixth century as an Orthodox Christian Church for the Byzantine Empire, also known as the Eastern Roman Empire or Byzantium. Today, the Hagia Sophia is one of the most-visited sites in Turkey, in the Sultanahmet neighborhood in the Fatih district. It is across the street from the Blue Mosque and next to the Topkapı Palace and the Basilica Cistern.

Throughout its tumultuous 1,500-year history, the Hagia Sophia has served as a place of worship for both Christians and Muslims.

• First construction: The Hagia Sophia was first commissioned by Byzantine Emperor Constantius in 360 CE when Istanbul was Constantinople and the capital of the Byzantine Empire. Greek Orthodox was the official religion of the Byzantine Empire, so the first Hagia Sophia was built for the Greek Orthodox Church. The first Hagia Sophia church burned to the ground in 404 CE when political riots broke out in Constantinople.
• Second construction: The Hagia Sophia was rebuilt in 415 CE by Roman Emperor Theodosius II and then burned down for a second time during the Nika riots.
• Third construction: The current Hagia Sophia was built in 537 CE, by Byzantine Emperor Justinian I. He commissioned architects Isidore of Miletus and Anthemius of Tralles to build the new church.
• Fourth crusade: During the Fourth Crusade, Constantinople fell under the control of the Latin Empire for a time, and Crusaders looted the Hagia Sophia.
• Istanbul: The Hagia Sophia underwent several significant changes during the conquest of Constantinople in 1453 by the Ottoman Empire under Ottoman Sultan Mehmed II (also called Mehmet the Conqueror). The city was renamed Istanbul, the main religion became Islam, and the Hagia Sophia was renovated into an imperial mosque.
• Remodel: During the reign of Selim II (1566–1574), the Hagia Sophia started to show signs of wear. Ottoman architect Mimar Sinan added structural supports to the building (including buttresses) and built two additional minarets, a sultan's lodge, and a mausoleum for Selim II.
• Transformation: After the Ottoman conquest, Islamic calligraphy designed by Kazasker Mustafa İzzet covered many of the original Christian mosaics, including one on the central dome of Jesus Christ. A mihrab, a prayer niche, was installed in a wall facing Mecca, and four minarets were added.
• Twentieth century: In 1934, President Kemal Atatürk, the first president of the Turkish Republic, secularized the building. In 1985, the Hagia Sophia was designated a UNESCO World Heritage site component as part of a series of buildings called the Historic Areas of Istanbul. The Ministry of Culture operated the Hagia Sophia Museum until 2020.
• Mosque: In July 2020, the Turkish Council of State and Turkish President Recep Tayyip Erdoğan re-designated the Hagia Sophia as a mosque and resumed prayer services in the building.

The Hagia Sophia measures 269 feet in length and 240 feet in width, with the domed roof stretching 180 feet above the ground. It was built in a grand Christian basilica style and is the most significant surviving example of Byzantine architecture. Notable details of the building include:

• Building materials: Emperor Justinian wanted to create a structure that represented the entire Byzantine Empire, using materials from every province to construct the basilica. The floor marble was produced in Anatolia, now eastern Turkey and Syria, and bricks for the walls and parts of the floor came from North Africa.
• Floor plan: The building is almost square in plan. It contains three aisles separated by columns, each containing a gallery of mosaics. Above the galleries are 40 windows, giving the impression that the roof is floating on air.
• Columns: The Hagia Sophia has 104 columns, many made of marble, imported from the Temple of Artemis in Ephesus—an ancient city near modern-day Selçuk, Turkey—and from Egypt.
• Dome: The main nave is covered by a central dome that is 107 feet in diameter and rises 180 feet above the ground. The dome is supported by four pendentives, one of the first large-scale uses of pendentives. The Hagia Sophia is the second-largest pendentive dome in the world, after St. Peter's Basilica in Rome. There are two semi-domes on either side, one at the altar and the other at the main entrance.
• Mosaics: The original Hagia Sophia was covered in Christian mosaics and frescoes. Many of the original Christian images were covered by the Ottoman Turks. One notable surviving mosaic in the Hagia Sophia is the Virgin Mary with the baby Jesus on her lap with a background of gold mosaics. Above the southwestern entrance to the Hagia Sophia is a mosaic of the Virgin Mary with Emperor Constantine, the first emperor of the Byzantine Empire, and Emperor Justinian I.

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