Hagia Sofia

Emperor Justinian wanted a cathedral finished faster than anyone thought reasonable, and got one. Ten thousand workers built Hagia Sophia in under six years, finishing the dome in 537. It took twenty-one years to prove the emperor’s hurry had a cost.

Earthquakes in 553 and 557 cracked the dome and its eastern arch. On the morning of May 7, 558, a third one brought the whole eastern section down, taking the altar, the ambon, and the ciborium with it. The bricklayers, it turned out, had used more mortar than brick and hadn’t waited for each layer to set before adding the next. The dome itself was also too shallow, which meant its weight pushed outward on the walls instead of down through the piers.

Isidore the Younger, nephew of one of the original architects, got the job of fixing his uncle’s mistake. He rebuilt the dome twenty feet taller and added forty ribs to carry the load down into the supports rather than out into the walls. It held until 989, when an earthquake took out the northwest section, and again in the 1340s, when cracks in the eastern arch went unrepaired long enough for mosaic and masonry to start falling on the clergy below.

The building has since been a cathedral, a Catholic cathedral under Crusader rule, an Orthodox cathedral again, a mosque, a museum, and, since 2020, a mosque once more. Constantinople fell only once. The dome kept trying.