Hagia Sophia

Hagia Sophia is a historic domed building in Istanbul, Turkey, originally completed in 537 CE as a Byzantine cathedral. It is renowned for its large central dome and for centuries was one of the largest and most influential examples of Byzantine architecture.

The interior features a vast nave crowned by a central dome about 31 metres across and decorated with mosaics, marble revetments and inscriptions. Visitors commonly view the main hall, the upper gallery and surviving mosaics and calligraphic panels; the structure combines elements of church and mosque architecture due to its multiple religious conversions. The building functions as a mosque in its current status and remains a major architectural and historic attraction in Istanbul.

Construction was ordered by Emperor Justinian I and completed in 537 CE by architects including Isidore of Miletus and Anthemius of Tralles. It served as the patriarchal cathedral of Constantinople until 1453, was converted to a mosque under Ottoman rule, became a museum in 1935, and was reconverted to mosque status in 2020.

Hagia Sophia sits in the Sultanahmet district of central Istanbul, adjacent to the Blue Mosque and the Topkapı Palace, within the historic peninsula that was the heart of Byzantium and later Ottoman Constantinople.

• Key dates and uses: Original construction was completed in 537 CE under Emperor Justinian I; later converted to a mosque in 1453 and reconverted to a mosque again in 2020 after being a museum.
• Viewing note: The dome and interior mosaics are best viewed from the nave and upper galleries; access to some upper areas is limited and managed for conservation.

What to See #

• Main dome: The central dome spans about 31 metres in diameter and reaches roughly 55.6 metres above the floor, forming the focal point of the interior space.
• Upper gallery: An upper gallery that was historically used by imperial and ceremonial visitors and now provides views of mosaics and interior decoration.