Warning: Spoilers follow for Game of Thrones, Season 6 Episode 2
Game of Thrones may be the only show on television on which the feeding of a newborn to vicious hounds is not the most shocking thing that happens in a given episode.
Still, it was pretty extreme—and on Sunday night’s episode, Ramsay Bolton’s string of familial murders was not limited to his baby half-brother’s demise. His stepmother went to the dogs as well, while his father met a less gruesome end at the point of a knife. The sequence was not merely a reminder of the character’s villainy, but also one more example of the reliance on real history in the George R.R. Martin books and TV show. After all, though Ramsay and his father did argue about military strategy, the catalyst for the crimes was something else: the baby’s birth, and the news that Lord Bolton had another son.
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As viewers were reminded, Ramsay started life as Lord Bolton’s illegitimate son, though he was later acknowledged by his father as a rightful heir. The new baby, by contrast, was born within the confines of a recognized marriage. In the fictional world of Westeros, different regions rely on different inheritance structures—for example, the practice of the Kingsmoot, which was also acknowledged on Sunday’s episode, complicates monarchic succession on the Iron Islands—but it’s generally a world in which legitimate birth is highly valued. (Common last names, like Snow, are used to signal illegitimacy.) It is also generally a culture in which male heirs take their fathers’ titles, skipping over female heirs.
That structure, though fictional, is rooted in the longstanding real-world practice known as primogeniture. For noble families, primogeniture was often coupled with an entail linking an estate and a title.
The basic idea of primogeniture is that the first-born, and in many cases the first-born son, gets everything. That means Ramsay Bolton is on track to inherit his father’s money, armies, title and any other perks of nobility. Should a baby brother challenge his legitimacy, however, he might stand to lose everything, as the system makes no provisions for sharing. (Younger sons, and often daughters, had to depend on gifts.)
“Illegitimate sons are not supposed to inherit at all. No matter what the father said, there was going to be a fight,” explains Nancy Goldstone, author of The Rival Queens and an expert in medieval history.”Even if the father said he was going to leave the estate [to an illegitimate child], there was going to be a contest after he died.”
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The original thinking behind primogeniture is that if you split up estates between the various children, after a couple of generations even the mightiest landowner’s holdings would be reduced to a patchwork of smaller estates. By giving everything to one heir, the size and power of the family is preserved. Though there were some alternate systems in use around medieval Europe, as Eileen Spring explains in her book Law, Land, and Family, pre-modern England was home to a notoriously strict version of this rule. One possible reason for that quirk was that, after the Norman Conquest in the 11th century, England boasted a strong enough monarchy that the king didn’t have reason to worry about noble families getting too powerful by holding onto what they had. Of course, as Thrones fans will note, pretty much the opposite is true in Westeros.
And in the real world, Goldstone notes, acknowledging an illegitimate son was way harder than it is on Game of Thrones. In England, a petition would have had to have gone all the way to the Pope or, after the Church of England was created, the King.
Perhaps the most famous example of traditional English inheritance law making people do pretty awful things can be found in another fictional drama: King Lear. Not only does an inheritance mess start the whole Lear family saga, but the side conflict between the sons of the Earl of Gloucester—one legitimate, Edgar, and one illegitimate, Edmund—highlights the tensions that can arise when only one son at a time can benefit from a father’s standing in society.
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In the U.S., abolishing residual British primogeniture law was an early priority after the Revolution. But the history of primogeniture is still a relatively recent one: though default primogeniture for people who died without a will was ended in the U.K. in 1925, it was only in 2011 that the British monarchy changed its rules to allow first-born daughters to claim the throne before their brothers. In 2013, the British parliament also considered a “Downton law” that would allow female heirs to inherit nobility titles—the law did not end up passing, though a version of it is still being considered.
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Write to Lily Rothman at lily.rothman@time.com