Unlike the Gladiator-loving Romans, the Byzantines were more into chariot racing (mostly because they were Christian and had banned Gladiatorial battles). Like, ridiculously into it. So into it that the fanclubs for the various racing teams became so huge, powerful, and intense in their rivalry that they could easily put any modern sport rivalry to shame. Young fans were also known to adopt trendy hairstyles (which often involved shaving a lot of the head except for bangs and side-braids, or just shaving the whole front half) based on the major nomadic cultures the Byzantines encountered, especially the Huns and Avars. These clubs became so intense in their rivalries, that they spilled over from sports into other issues, mostly politics and religion (different clubs tended to support different theological teachings and would argue about them even while cheering on their teams in the Hippodrome). All of this exploded into a giant riot in 532 CE, when a brawl between the two biggest fan clubs (The Blues and The Greens, named for the teams they supported) spiralled completely out of control and turned into a city wide riot that burned down a huge amount of Constantinople (including the original Hagia Sophia). Some political rivals of Emperor Justinian used this as an opportunity to try to launch a coup and use the riot to help them. After being persuaded to stay and face the rioters head on by his awesome wife Theodora, Justinian ordered his best general Belisarius to bring an end to the riots. Which he did. Brutally. An estimated 30,000 people were killed by Belisarius’ soldiers (in a city of roughly 500-600,000 people). And that’s why fandom rivalries are really really bad and never end well.
I should note, all of this only applies to the Early Byzantines. I got nothing on the later Byzantines.
To really bring the point home on just how bad ass Theodora was, the story goes that just before Justinian was ready to flee, Theodora had insisted on staying and when Justinian pointed out she might be killed, Theodora replied, “Purple is a lovely color for a burial shroud.”
Context: purple was a heinously expensive dye legally only allowed to be worn by the emperor (& empress). She was saying she would rather die as empress than live and be deposed.