You've read our recap of last night's Game of Thrones and you probably cheered all the disgusting things that happened at Joffrey and Margaery's wedding, then worried about schadenfreude as a result. Here, we check in with the deep background of the world of Westeros, sketched out in George R. R. Martin's novels, to give context to some of the crazy goings-on this week without going into spoiler territory.

Bran's Visions

We've known for a while now that Bran is a warg (the books also use the word "skinchanger") who can leap into the mind of his wolf, Summer. But this week, he used his mental powers to jump into the mind of one of those weird trees with the faces in them, and saw a jumbled vision that included the throne room covered in snow, a giant Weirwood somewhere beyond the wall, a gross-looking corpse and the silhouette of a dragon casting a shadow over King's Landing.

The imagery is there mostly to pique our interest and keep us invested in Bran's (slow-moving) storyline, but it's good to know some background on those weird trees. Westeros, especially in the north, was once populated with magic elf-like creatures called the Children of the Forest, who were slowly wiped out thousands of years ago with the arrival of the First Men (the humans who the Starks trace their lineage to) and the Andals (conquerors from the west who established the now-dominant religion of The Seven). Most of the Weirwoods were chopped down, but the ones that remain offer a magical link to ancient times, when the Wall was first built and the Children of the Forest and First Men waged war with the invading White Walkers. Perhaps this is what Bran can tap into as his psychic powers expand.

Stannis Burning the Heretics

Our brief glimpse at Dragonstone this week sees Stannis, his wife Selyse, and priestess Melisandre preside over the burning of heretics, including someone who appears to be Selyse's brother. In the books, this incident occurs in a slightly different format for slightly different reasons. It's Selyse's uncle, a powerful lord named Alester Florent, who is burned at the stake, and largely because he attempts to make peace with the Lannisters following Stannis' defeat at the Blackwater.

That was probably too much backstory for the show to include, so instead the unnamed Florent is said to be dying just for the sin of refusing to strike down his religious idols and conform to Stannis' worship of Melisandre's Red God, R'hllor (also known as the Lord of Light). What the show does present correctly is Selyse's fanaticism for the religion, which is stronger and more devout than Stannis'. He goes along with partly because  Melisandre paints him as a messianic figure destined to save the world, and partly because her magic seems to work (he'll certainly be thrilled to hear that Joffrey's dead). But Selyse, a somewhat addled woman in a loveless marriage who failed to provide Stannis with a male heir, believes Melisandre's spiel wholeheartedly.

Roose Bolton, Ramsay Snow, and Reek

Okay, so we're finally getting a good look at the Dreadfort now that Roose Bolton is home from all the fighting. What's the situation here? Bolton, as we know, is a powerful castellan in the North who wears a flayed man on a cross on his banners. Thanks to his betrayal of the Starks, he's been handed control of the North by the Lannisters, but that control remains mostly theoretical considering that the realm has always been ruled by House Stark and Bolton's family is best-known for being creepy and practicing the dark arts of torture long after they were banned on the grounds of decency.

It doesn't help that Roose has no legitimate heir—his only son is a bastard, Ramsay Snow, who spent all last season torturing Theon and molding him into a pathetic slave called Reek, finishing with his castration at the end of season three. Roose is a cold, calculating sociopath, but Ramsay is even more cruel and unpredictable (he bears the last name Snow, like Jon, because it is given to all bastard children born in the North). In the books, Ramsay (a product of Roose raping a commoner's wife on her wedding night) is even more sensitive about his illegitimate status and was raised by a creepy manservant called Reek (which just makes things even more confusing).

Ramsay's molding of Theon into the new Reek happens entirely "off-screen" in the books (there's no sign of Theon in books three or four), so all the scenes we're presented with here are entirely new material. But Ramsay's peculiar way of trying to impress his impassive father, and Roose's cautious respect for his son's insanity, sticks close to the source material. Another thing worth noting: Roose returns to the Dreadfort with a wife, a portly lady called Walda, who is one of Lord Walder Frey's granddaughters from The Twins, where the Red Wedding happened. In the books, the two were married as a political match offered by Walder, who said he would give Roose his bride's weight in silver if he married a Frey daughter. Roose, ever-calculating, chose the largest available bride.

Iron Bank

It was just a brief mention, but in Olenna's conversation with Tywin after the wedding, where Tywin bemoaned the extravagance of the affair, the Tyrell matriarch reminded him that the Iron Bank would have its due. Based in the free city of Bravoos across the water, the Iron Bank is the richest, most powerful financial institution in the world, and the Seven Kingdoms is heavily in its debt. When Littlefinger was Master of Coin, he kept a lot of plates spinning to keep money moving through Westeros despite all this debt, but he's busy doing other stuff now and his replacement Tyrion is, at the end of this episode, in a heap of trouble. The Iron Bank is not an issue that will go away for the Seven Kingdoms.

Dontos the Fool

Remember this guy? He's present in the premiere of season two, where he shows up drunk for a tournament in honor of Joffrey's birthday. The evil king gets ready to order his death, but Sansa intervenes and convinces him to make Dontos a fool instead, presenting it as a more humiliating life. In last week's episode, Dontos showed up to thank Sansa for her kindness, and this week he appeared to spirit her away when Joffrey started to choke, suggesting he's at least part of the plot to kill the king.

In the books, there's a little more background to Dontos, who is the only surviving member of the extinct House Hollard, which was wiped out after a failed uprising against the Mad King, an incident called the Defiance of Duskendale (because he was a child, he was spared from the ensuing bloodshed). Sansa meets more frequently with Dontos, who thanks her for sparing him in the second book and remains in her debt through the third. Of course, there's more to this story on the way.