The whole thing began because two men failed to die properly.
On 10 January 532, the city prefect Eudaimon carried out a scheduled execution of rioters convicted of murder during disturbances after a chariot race. Most of the condemned died without incident. Two did not. The scaffold failed - the timber gave, or the rope slipped, the sources are not entirely clear - and a Blue partisan and a Green one swung down, alive. Monks from a nearby monastery pulled them to the church of St Laurence, where they sat under guard, technically prisoners, technically still awaiting execution.
On January 13, Justinian made a decision that looked reasonable and turned out to be catastrophic. He announced chariot races at the Hippodrome and commuted the two men’s sentences to life imprisonment. The crowd that filled the vast structure next to the palace - perhaps 100,000 people - was not grateful. They wanted the men released outright. Justinian ignored the demands. By race 22, the partisan chants of “Blue” and “Green” had merged into a single word. Nika. Victory. Conquer. Both factions turned on the palace together.
What followed was a week of fire.
The Blues and Greens were not simply sports fans or even football hooligans of the 20th century. In Constantinople of that era they had spent decades functioning as the closest thing the Byzantine capital had to organised popular politics: crowding the hippodrome to shout policy demands between races, wielding genuine street-level force, wielding genuine political weight. Faction brawls after races were common enough - violent, occasionally lethal, structurally similar to the worst football hooliganism. What was different about January 532 was that both factions united. That almost never happened. When it did, the combined mass became something closer to a popular uprising than a post-game riot.
They also had a longer list of grievances than two imprisoned rioters. Justinian’s tax minister John the Cappadocian had been extracting money from debtors through methods that alarmed even Byzantine contemporaries, and he was particularly despised by the senatorial elites he had targeted directly. The legal reforms that had burnished Justinian’s early reign had stalled. A war against Persia had ended badly at Callinicum in 531. All of this gave the riots a depth that was not obvious on the first day, and almost certainly explains why a complaint about two hangings escalated into something that half-destroyed a city.
By the fifth day the fires had consumed much of central Constantinople. The Hagia Sophia that the emperor Theodosius II had built in 415 was gone. The ceremonial Chalke Gate was ash. Large sections of the city between the Hippodrome and the sea had burned. Justinian had already sacked John the Cappadocian and his legal minister Tribonian as concessions; the crowd had not been appeased. They wanted someone else in the palace entirely.
The someone they settled on was Hypatius - a nephew of the late emperor Anastasius, with a credible dynastic claim and, according to Procopius, very little desire to be crowned. Whether he was carried from his house against his will or whether he enjoyed the moment more than his later protests suggested, the crowd draped the imperial regalia on him in the Hippodrome and declared him Augustus. Justinian, watching from across the palace wall, faced something that looked very much like the end of his reign.
He considered running. The sea lay close, boats were available, and enough of his court was already arguing that a retreat to Thrace - regroup, raise fresh troops, return - was the sensible option. His wife, the Empress Theodora, refused.
What Theodora said has come down through Procopius, who was elsewhere an unflattering chronicler of her life and therefore has no obvious reason to have invented the speech. The argument she made was simple: she had been empress and intended to remain one, in the palace or in a grave. The phrase Procopius records is precise enough to stick in the memory over fifteen centuries: purple makes a fine winding sheet. The imperial colour that no one but the emperor and empress could legally wear would serve as her shroud if it came to that. She was not leaving.
Justinian stayed.
What happened next was quick and brutal. The eunuch Narses walked into the Hippodrome alone and unarmed, carrying a bag of gold given to him by Justinian, and made his way to the Blues’ section. He reminded the Blue leaders that Justinian had historically favoured them over the Greens, that the man currently being crowned had no particular loyalty to either, and distributed the gold. In the middle of Hypatius’ coronation ceremony, the Blues separated from the Greens and the two sides resumed their traditional hatred, throwing stones at each other.
Belisarius and the general Mundus then entered the Hippodrome from the north with the imperial guard. The soldiers worked through the crowd. Procopius gives a figure of 30,000 dead by the end of the afternoon. Even discounting for his tendency toward dramatic numbers, the killing was enormous. Hypatius was captured alive. He protested his innocence, sincerely or otherwise. Justinian had him executed the following morning along with his brother Pompeius, and their bodies were thrown into the sea. The senators who had backed the uprising were exiled and their properties confiscated. John the Cappadocian, dismissed five days earlier as a concession to the rioters, was reinstated.
In the space cleared by the fire that had consumed the old Hagia Sophia, Justinian commissioned a new one. The architects Isidore of Miletus and Anthemius of Tralles spent five years building a structure with a dome 31 metres across and rising 55 metres from the floor - larger than anyone had previously managed to construct. It was consecrated in December 537 and it is still standing, in Istanbul, visited by millions of people each year who mostly do not know they are looking at a building that exists because of a riot.
The version of January 532 that remembers it as Justinian’s finest hour glosses over the part where he was packing for Thrace. What kept him in Constantinople was not strategic vision or imperial nerve. It was an empress who had decided she would rather die wearing purple than live without it. The Hagia Sophia was built by a man who almost wasn’t there to commission it - in a city that nearly burned to nothing - because a scaffold broke, and two men failed to die on a January morning.