The Targaryens have their dragons and their wigs. The Starks have their wolves and their ability to (sometimes) time travel via psychic trees. But only one family has managed to hang onto the the Iron Throne since book one of the Song of Ice and Fire series, and that's the Lannisters of Casterly Rock. What they lack in magical pets they make up for with their shared family values of manipulation, scheming, and being rich as hell. There's evil queen Cersei, kind-of-less-evil knight Jaime, and baby brother Tyrion, the witty ladies' man who had better not die in the next book or fans will quite possibly lead a revolt.
So how did Maester George R.R. Martin come up with Westeros's least magical, most powerful family?
Well, like most fantasy authors, Martin borrows directly from real world history (with a few dragon-based embellishments). Westeros is Fantasy Britain, and the "Game of Thrones" itself is a high octane retelling of the English War of the Roses. And while the Starks and the Targaryens pull from quite a bit of folklore and mythology, the Lannisters are almost entirely based on real people, who really did spend their time plotting and throne-stealing and murdering little boys.
To begin with, the House of Lannister seems to be pretty closely based on the real life House of Lancaster. To vastly simplify actual history, the War of the Roses was a struggle between the Yorks and the Lancasters over England's throne. The Yorks/Starks were repped by white roses, while the Lancasters/Lannisters wore red roses (and yes, GRRM kept the color scheme). The whole trouble began when Henry IV, a Lancaster, led a rebellion against the "mad" king Richard II, because he'd inherited the throne ahead of his deceased older brother's sons (and also he was boring and nobody liked him).
Henry IV won the crown, much to the annoyance of the Yorks, who felt that they were legally next in line to rule England. Fast forward a couple of Henrys, and the timid King Henry VI married a hot, wily French woman called Margaret of Anjou.
Margaret took one look at the meek, sickly king and decided that she'd just have to start running things herself. She was also very close to one of her "allies," the Duke of Somerset, leading people to start spreading rumors that her son, Edward, was not the king's true child.
This escalated to the point that Richard of York, the recently appointed "Protector of the Realm" (i.e. Hand of the King) raised an army against Margaret to take back the throne... and wound up with his head on a pike. York's son pulled a Robb Stark and took up his father's cause, though, and Margaret retaliated with a vengeance. She'd do anything to see her son crowned king... even though most sources report that he was an unusually cruel and violent boy.
Much like Joffrey, lil' Edward was murdered while still a youth, and Margaret eventually lost her throne to Richard of York's son (also called Edward because the English royal family loves using the same five names over and over again).
So... yeah, Cersei is basically Margaret of Anjou, with some storybook evil queen vibes thrown in there for flavor.
But Cersei is also based on a later queen of England: poor Anne Boleyn, wife of the infamous King Henry VIII. Anne was Henry's second wife, and he created the whole dang Church of England just to marry her. However, she made the fatal error of giving birth to a daughter instead of a son, so the king accused her of sleeping with her own brother and had her imprisoned in the Tower of London. Unlike Cersei, Anne was probably innocent of the accusations, but also unlike Cersei, Anne was beheaded for her "crimes" anyway.
At least Cersei got to keep her head...
Jaime doesn't have quite so many clear parallels in the Lancaster clan. He's a little bit like Anne Boleyn's brother, George, who was executed alongside her for incest. George was also well known for his good looks and his intense arrogance, which is Jaime all over.
Berlichingen was an actual knight with a metal hand in the 1500's—although his hand was iron, not gold. He was famous for fighting with this badass prosthetic, which could hold a shield, horse reins, or even a quill. He was also famous for coining the phrase "Er kann mich am Arsch lecken," which translates to, "He can lick my ass."
Cesare Borgia, on the other hand, was so hot and dastardly that he was the literal inspiration for Machiavelli's The Prince. He started out as a man of the church, which meant that, like Jaime, he was under oath and *supposed* to be celibate. But Cesare eventually got bored of that, had a wildly successful military career, murdered his brother in a kingslayer-style betrayal, and very possibly had a bastard child with his sister-in-law. Which isn't quite sleeping with your own twin... but it's not great, either.
Jaime does seem to be on a nobler path now, though, so hopefully all the lying and murdering and incest is behind him (although that does seem to be his main skill set).
Finally, we have Tyrion. The much maligned baby of the family. The one Lannister who starts the series as a reasonably nice person. The fan favorite character who genuinely seems to care about poor people and working plumbing systems. Just about the only guy in the whole dang epic who has both a heart and a sense of humor.
And who is he based on? One of the most infamous villains in all of English history.
Yes, poor Tyrion is more than a little bit inspired by King Richard III. You know, the vicious Shakespearean villain who murdered his own nephews to steal the crown?
Before you get too mad on Tyrion's behalf, though, you should know that history is written by people like Cersei Lannister. It's very likely that Richard III himself wasn't actually a bad dude. He was a fiercely smart politician and an excellent soldier who maybe didn't get along perfectly with all of his siblings, but there's not a ton of evidence that he actually murdered his nephews. He was also a very successful ruler, at least until his successors killed him and destroyed basically all evidence of his reign. He cared deeply about bringing justice to the common people of the realm, and most of his contemporaries describe him as having a "good heart" and being a champion of the poor.
Much like Tyrion, though, Richard was easy for his rivals to demonize. He was a short man with scoliosis, giving him a warped spine as an adult. The condition didn't really affect his ability to fight or to rule, but his enemies took it and ran with it. According to them, he was a hunchback, which meant that he was evil, which clearly meant that he murdered his own nephew to steal the throne, just like when Tyrion murdered Joffrey.
So will the Lannisters be able to hold out against all those dragons and zombies and wolves? Will they cling onto the throne for another five books? I'm guessing not... but whatever happens, if history is any indication, they've still got some drama to unfold.