"The trouble had started in the Hippodrome, the popular heart of the city. There the charioteers and circus performers - sports heroes like the baseball and football players of our time - were traditionally grouped into two rival factions, the Blues and the Greens. Over the years, these factions had evolved into the equivalent of political parties. As a rule, the emperor found it easy to maintain his own power by playing one off against the other, but occasionally, the Blues and Greens united. The rivals had done so under Theodosius II, for example. On that occasion, their reconciliation had been effected for the constructive purpose of extending and strengthening the walls of the city after an earthquake. (The defenses they erected were to survive all assaults for 1,000 years.) Now they united once again, this time in a destructive mood. Under pressure of heavy taxation, corruption, and general discontent, they joined forces in order to depose Justinian.
While the fire raged, Justinian went in person to the Hippodrome, hoping to appease the angry mob with a repentant speech. When his words failed to impress the angry crowd, the emperor’s confidence faltered. Uncertain what action to take, he turned to his strong-minded wife, Theodora, who fortified his resolve with the exhortation: “If there were left to me no other safety but in flight,” she declared, “I would not fly. Those who have worn the crown should never survive its loss. Never will I see the day that I am not hailed Empress. If you wish to fly, Caesar, well and good; you have money, the ships are ready, the sea is clear; but I shall stay. For I love the old proverb that says, ‘The purple is the best winding-sheet.’” Order was finally restored by the army, which put the mob to rout, leaving 30,000 corpses on the floor of the Hippodrome. Justinian’s rule was secure, but Hagia Sophia lay in ruins. Here was a supreme challenge for Justinian the Builder. It became his ambition to create a mightier church."
The Serpent Column is located at the place known, in ancient times, as the Hippodrome, where the Nika Riots started.