Early in Season 4, Game of Thrones shocked its viewers when the monstrous young King Joffrey suddenly dropped dead at his wedding feast, apparently from poison. Shortly afterward, George R.R. Martin, the author of the book series the show is based on, told Entertainment Weekly that he was inspired by a similar mysterious death that occurred all the way back in the year 1153:

"I based it a little on the death of Eustace, the son of King Stephen of England. Stephen had usurped the crown from his cousin, the empress Maude, and they fought a long civil war and the anarchy and the war would be passed down to second generation, because Maude had a son and Henry and Stephen had a son. But Eustace choked to death at a feast. People are still debating a thousand of years later: Did he choke to death or was he poisoned? Because by removing Eustace, it brought about a peace that ended the English civil war. Eustace's death was accepted [as accidental], and I think that's what the murderers here were hoping for - the whole realm will see Joffrey choke to death on a piece of pie or something. But what they didn't count on, was Cersei's immediate assumption that this was murder."

Now, Martin has said elsewhere, "I'm not a historian by any means but I read a lot of popular history." And academic historians are a bit more guarded than Martin about how Eustace died. Ralph Henry Carless Davis writes, "He died, quite suddenly … Some said that he died of grief, others that he had been smitten by St. Edmund in punishment of damage which he had done to his abbey's lands."

But the sudden death of the wicked Eustace at dinner, shortly after mistreating some monks, has a long pedigree in English tradition. Gervase of Canterbury, a 12th-century English chronicler, wrote: "When he sat down at table to eat … at the first taste of food he fell into a miserable madness, and because of the arrogance he had shown to the Martyrs he underwent the dire pains of death." Two other 12th-century writers say that Eustace choked on a dish of eels, according to author Roberta Gellis. A 19th-century book tells of how Eustace destroyed Bury St. Edmunds abbey's crops, and recounts: "Having thus taken revenge on the monks, Eustace sat down to dinner; and, as the story is told, was choked by the first morsel he attempted to swallow."

Eustace's death came toward the end of the English historical period known as the Anarchy, when cousins Stephen (Eustace's father) and Matilda (or Maude) warred for the throne. Martin was heavily influenced by this period — last December he published a novella describing a similar war, set hundreds of years before the events of the TV series, between two Targaryen siblings — only he included dragons. Steven Attewell, a history PhD from UC Santa Barbara, has written about how Martin drew on the Anarchy for that work: "Like a DJ, Martin samples and remixes from historical events and figures to accomplish the literary effect he wants to achieve."

Season 3's marquee shocker — the massacre of Robb Stark, Catelyn Stark, and their army at the Red Wedding — was also based on real historical events, this time in Scotland: the Black Dinner of 1440 and the Glencoe Massacre of 1692. The Week describes those historic bloodbaths in more detail here. "No matter how much I make up, there's stuff in history that's just as bad, or worse," Martin said last year.