Hagia Sophia Timeline

(537 - Present)

The Hagia Sophia, located in Istanbul, Turkey, is one of the world's most iconic architectural masterpieces. Originally built as a Christian cathedral under Byzantine Emperor Justinian I, it served as the spiritual center of Eastern Orthodoxy for nearly 1,000 years. After the Ottoman conquest of Constantinople in 1453, it was converted into a mosque. In the 20th century it became a museum, and in 2020 it was reconverted into a functioning mosque. Its massive dome and rich history make it a symbol of both Byzantine and Ottoman heritage. More Less

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Byzantine Era

Construction of first Hagia Sophia church

360

The first church on the site, known as the Megale Ekklesia, was completed in 360 under Emperor Constantius II during the reign of Constantine's dynasty. It served as the cathedral of Constantinople until it was destroyed by fire in 404 following riots.

Image source: Hagia Sophia

Second church destroyed by Nika riots

532

The second Hagia Sophia, rebuilt by Theodosius II after the fire of 415, was burned down during the Nika riots in January 532, a violent uprising against Emperor Justinian I that devastated much of Constantinople.

Image source: Nika riots

Justinian I commissions current Hagia Sophia

Feb 23, 532

Emperor Justinian I ordered the construction of a grand new basilica just weeks after the Nika riots, appointing the architects Anthemius of Tralles and Isidore of Miletus to design what would become one of the greatest buildings of antiquity.

Hagia Sophia consecrated as cathedral

Dec 27, 537

After only about five years of construction, the new Hagia Sophia was consecrated on December 27, 537. Its massive dome appeared to Byzantines to be suspended from heaven by a golden chain, becoming a symbol of Justinian's reign and Byzantine power.

Partial collapse of original dome

558

An earthquake in 558 caused the original dome to partially collapse. Isidore the Younger rebuilt it with a higher profile, and the restored church was rededicated in December 562 with a new dome that survives in modified form today.

Earthquakes damage the structure

989 - 994

A major earthquake in 989 collapsed the western dome arch. Armenian architect Trdat was commissioned for repairs, which were completed around 994, restoring the building's grandeur after years of work.

Sack of Constantinople during Fourth Crusade

1204

Crusaders of the Fourth Crusade sacked Constantinople in April 1204, desecrating Hagia Sophia and looting its treasures. During the subsequent Latin Empire period, the cathedral was used by Roman Catholic clergy under Venetian influence.

Image source: Sack of Constantinople

Byzantines recapture Constantinople

1261

Michael VIII Palaiologos reclaimed Constantinople in 1261, restoring Hagia Sophia to Orthodox worship. The building, though weakened by decades of neglect, remained the spiritual heart of the revived Byzantine Empire.

Image source: Empire of Nicaea

Addition of Deësis mosaic

1261 - 1300

Following the Byzantine reconquest, the celebrated Deësis mosaic depicting Christ, the Virgin Mary, and John the Baptist was created in the upper gallery, widely regarded as the finest Byzantine mosaic in the building.

Repairs by architects Chalcocondylis and Rhoilas

1346 - 1355

An earthquake in 1346 damaged portions of the dome and parts of the building collapsed. Repairs led by architects Astras and Peralta were carried out over several years, preserving the structure for another century of Orthodox worship.

Ottoman Era

Conversion into imperial mosque

1453

Under Mehmed II, Hagia Sophia became Aya Sofya Mosque. Christian icons were covered or removed, and Islamic features were gradually introduced while the building retained much of its original character.

Construction of first minaret

1453 - 1455

A brick minaret was added shortly after the conquest in the southeast corner, marking the building's transformation into a mosque. Three more minarets would follow under later sultans.

Image source: Little Hagia Sophia

Final siege of Constantinople begins

Apr 6, 1453 - May 29, 1453

Ottoman Sultan Mehmed II besieged Constantinople for 53 days. Hagia Sophia stood at the heart of the city as the last Byzantine emperors sought Western aid that never meaningfully arrived before the walls fell.

Image source: Fall of Constantinople

Fall of Constantinople to the Ottomans

May 29, 1453

Mehmed II entered the city and proceeded to Hagia Sophia, converting it into an imperial mosque. This event marked the end of the Byzantine Empire and began the building's Ottoman chapter.

Bayezid II builds minaret and madrasa

1509

Following earthquake damage in 1509, Sultan Bayezid II commissioned a new minaret and added a madrasa adjacent to the mosque, expanding its role as a center of religious learning.

Selim II adds mausoleums and restorations

1573 - 1577

Chief architect Mimar Sinan reinforced the aging structure with supports and built two large mausoleums for Selim II and later sultans, beginning the tradition of royal burials at the mosque complex.

Image source: Selim II

Addition of mihrab, mimbar, and sultan's lodge

1739

During renovations ordered under Mahmud I, a mihrab, mimbar, sultan's lodge, and library were added or renovated, further integrating the Byzantine structure into Ottoman religious life.

Fossati brothers restoration

1847 - 1849

Swiss architects Gaspare and Giuseppe Fossati undertook an extensive restoration under Sultan Abdülmecid I, strengthening the dome and vaults, cleaning mosaics, and adding calligraphic medallions by Kazasker Mustafa İzzet Efendi.

Image source: Fossati brothers

Calligraphic roundels installed

1847 - 1849

As part of the Fossati restoration, eight massive wooden medallions bearing the names of Allah, Muhammad, the early caliphs, and Hasan and Husayn were hung in the nave, becoming iconic features of the interior.

Image source: Kazasker Mustafa Izzet Efendi

Earthquake damages dome and minaret

1894

A powerful earthquake struck Istanbul in 1894, damaging the dome and destroying part of the main minaret, prompting further repairs by the Ottoman state in the final decades of empire.

Image source: 1894 Istanbul earthquake

Modern Status

Ottoman Empire collapses; mosque closes

Nov 1922 - 1924

Following the abolition of the sultanate and the founding of the Turkish Republic under Mustafa Kemal Atatürk, Hagia Sophia's role changed dramatically as the new government pursued secularizing reforms.

Image source: Abolition of the Ottoman sultanate

Supreme Court rejects mosque status change

2013

Turkey's Council of State declined petitions seeking to reopen Hagia Sophia for Muslim worship, upholding its status as a museum amid ongoing public and political debate over its future.

US House resolution urges preservation as museum

Jul 2019

A US congressional resolution called on Turkey to maintain Hagia Sophia as a museum without alteration, reflecting international concern over reports that its status might change under pressure from conservative groups.

Council of State annuls 1934 museum decree

Jul 10, 2020

Turkey's highest administrative court ruled that the 1934 cabinet decision converting Hagia Sophia into a museum was unlawful, clearing the way for the building to return to use as a mosque.

Image source: Council of State (Turkey)

Reconversion into a mosque

Jul 24, 2020

A presidential decree transferred Hagia Sophia to the Diyanet for use as a mosque, and Friday prayers were held on July 24, 2020. The decision drew international reactions, and UNESCO asked for more information about potential impacts on the World Heritage site.

Museum and Restoration

Mosaic conservation campaigns begin

1930 - 1955

Teams including Thomas Whittemore of the Byzantine Institute of America uncovered and conserved the great Byzantine mosaics, revealing masterworks such as the Deësis panel and portraits of emperors and empresses.

Atatürk converts Hagia Sophia into museum

1935 - Feb 1, 1935

By decree of Atatürk, Hagia Sophia was secularized and opened as a museum on February 1, 1935. Mosaics long hidden under plaster were uncovered and displayed, making the building a major tourist and scholarly destination.

UNESCO World Heritage listing

1985

The Historic Areas of Istanbul, encompassing Hagia Sophia and other landmarks, were inscribed on the UNESCO World Heritage List, recognizing their outstanding universal value to humanity.

Image source: Historic Areas of Istanbul

Major structural restoration launched

1990 - 2009

Turkish authorities carried out multi-decade restoration work addressing the dome, buttresses, mosaics, and foundations, using modern techniques to stabilize the nearly 1,500-year-old monument.

Discovery of Baptistery and underground structures

2000 - 2010

Archaeological surveys revealed previously unknown subterranean chambers, cisterns, and structures beneath and around the building, deepening understanding of the site's layered history.