Built for the emperor Justinian I in under six years, and finished in 537 (532–537)
The third church on the site; its predecessor burned in the Nika riots of 532
Geography · Landmarks & wonders
The Hagia Sophia
completed AD 537
Turkey — Istanbul, the old city of Constantinople
Justinian's great domed church of Holy Wisdom, finished in 537 after less than six years' work and for a thousand years the largest enclosed space in the world. Cathedral of Constantinople until 1453, then an imperial mosque, then a museum from 1935, and a working mosque again since 2020, it is the defining monument of Byzantine architecture.
How to spot them
- ▸Quiz clue: 'Justinian', 'Anthemius of Tralles', 'Isidore of Miletus', 'pendentive', 'Holy Wisdom'
- ▸A vast shallow dome that seems to float on a ring of windows
- ▸Church, then mosque, then museum, then mosque again
- ▸Its Greek name means 'Holy Wisdom'
Key facts
Designed not by architects but by two Greek geometers, Anthemius of Tralles and Isidore of Miletus
Anthemius also wrote on conic sections and burning mirrors
Its dome rests on pendentives — curved triangles that carry a circle on a square
Among the first fully pendentive domes, and the model for a thousand years of domed building
For nearly a thousand years it enclosed the largest interior space on earth
Only Seville Cathedral, finished in the 16th century, finally exceeded it
Its dome collapsed in 558 and was rebuilt steeper by the original architect's nephew (558)
Isidore the Younger raised it about 6 m, giving the ribbed profile seen today
Its Christian mosaics were plastered over after 1453 and uncovered again in the 20th century
The Deesis, the Empress Zoe panel and the Virgin in the apse were revealed by the Byzantine Institute from 1931
A Norse mercenary of the Byzantine emperor's guard scratched his name on a marble parapet
Runic graffiti in the south gallery, usually read as 'Halfdan'
Turned into a museum by Atatürk's government in 1935, and back into a mosque in 2020 (1935 and 2020)
A Turkish court annulled the 1934 cabinet decree in July 2020
Quick-fire facts
- •The dome is about 31 m across and rises some 55 m above the floor
- •It was the cathedral of Constantinople from its dedication until the city fell in 1453, apart from 1204–1261 when Latin crusaders installed their own hierarchy
- •Mehmed II converted it to a mosque immediately after the conquest in 1453; the four minarets were added over the following century
- •The architect Mimar Sinan buttressed it in the 16th century and took it as the model for his own great mosques
- •It lies within the UNESCO World Heritage Site 'Historic Areas of Istanbul', inscribed in 1985
- •The giant calligraphic roundels naming God, Muhammad and the first caliphs were added in the 19th century by Kazasker Mustafa İzzet
- •Common misconception: the legend that Justinian cried 'Solomon, I have outdone thee' at its dedication is a later story, not contemporary record
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Sources
- UNESCO World Heritage Centre — Historic Areas of Istanbul
- Rowland J. Mainstone — Hagia Sophia: Architecture, Structure and Liturgy of Justinian's Great Church