The original basilica, called the 'Great Church,' was built on the orders of Constantius II and consecrated on this date, becoming the cathedral of Constantinople. It burned during riots in 404 and was rebuilt, but the site's ultimate fame would come with Justinian's domed masterpiece in 537. Little of the original structure survives beneath its successors.
When the Great Church rose beside the imperial palace in Constantinople, the city was barely a generation old as the empire's new capital, and Constantius II wanted a cathedral to match its ambitions. The timber-roofed basilica took its name, Hagia Sophia, from the Greek for 'Holy Wisdom,' not from any saint.
That first building did not last. In 404, riots following the exile of the fiery preacher John Chrysostom set the church ablaze, and a second version had to be built by Theodosius II. Fragments of that second church, including sculpted marble blocks showing lambs, were unearthed by archaeologists in the 1930s beneath the courtyard of the current, far grander sixth-century building.
The site's true immortality came later, when Justinian I raised the current Hagia Sophia after the Nika riots destroyed its predecessor in 532. But that spectacular dome, one of architecture's supreme achievements, stands on ground first consecrated for worship on this October day in 359, a reminder that even revolutionary buildings often rest on humbler foundations.
Key people: Constantius II