"At times, [George R.R.] Martin clearly invokes the Wars of the Roses, what with the house of Lannister (Lancaster) locked in a rivalry with the house of Stark (York), and there are parallels to Mongol invasions (the Dothraki), the Hanseatic League (the Free Cities), and so forth. But searching too intensely for the "real" elements beneath the text [of Game of Thrones] is pointless, since what is truly captivating about Martin's world -- the detailed descriptions, the strong dialogue, the multifaceted characters, the intricate plots and subplots -- stems from not from his source material but from his own imagination. That turns out to be the true magic"

further to the post re. fantasy on TV as "neo-Medieval guff" versus s.f.'s speculative projection into the future
-- here's an interesting piece by a real-deal Medieval historian who deftly unpicks the contention that GoT is unusually realistic and gritty for post-Tolkien fantasy - the truth is life in the Middle Ages was drab and uneventful for the majority of the population, with violence a rare occurrence and sources of entertainment few and far between... most battles were short and relatively unbloody

the piece makes clear that what is truly Medieval about GoT is not its depiction of grim 'n' grisly life... but that it is exactly the same sort of epic saga -- unrealistically packed with action, violence, marvellous and terrifying monsters, faery creatures and magical powers etc-- that people in the Middle Ages told to each other, in order to alleviate the unremitting tedium of their lives:

"I'm glad Martin takes all the liberties he does, because I prefer my literature exciting. Medieval people did also, which is why their own most popular literary creations were nearly as fantastic as Martin's."

plus ca change eh