Redditor Art4261 noticed that the insane and murderous Roman emperor Caligula looks a lot like the insane and murderous King Joffrey Baratheon in Game of Thrones--at least as the latter is portrayed by actor Jack Gleeson.
Caligula is Latin for "Little Boot"--the nickname of Gaius Julius Caesar Geramanicus. Here's a sample of his madness:
He went out of his way to humiliate the senate (Suetonius says that he intended to make his horse consul), and encouraged treason trials for his own financial benefit. He also insisted on being treated as a god (in contrast to the wiser policy of Augustus). Excavations in the Roman forum in the summer of 2003 confirmed that he incorporated the ancient Temple of Castor and Pollux within his palace - a sacrilege reversed by his successor Claudius I.
Gaius had three sisters, with whom he was alleged to have committed incest, and they were given unprecedented public honours, being included in the soldiers' oath of allegiance.
Will Joffrey appoint his horse to the small council?
As for the incest.... seriously, was there anyone back in the day that wasn't screwing their own family member??