Read George R.R. Martin's Original Game of Thrones Outline
George R.R. Martin's initial plan for his A Song of Ice and Fire books was very different from the story we've come to love in print and on TV—as you can see from the original outline he sent to his publisher. As i09 reported back in 2015, the three-page outline was posted on Twitter from the account of British bookseller Waterstones. Though the tweet has since been deleted, the outline's authenticity was reportedly confirmed by the HarperCollinsUK account.
Warning: Spoilers ahead!
The document roughly outlines Martin's ideas for A Song of Ice and Fire—which, at that point, was a trilogy—and included 13 chapters of the first book, A Game of Thrones. (Martin warned the publisher, "I see all three volumes as big books, running about 700 or 800 manuscript pages, so things are just barely getting underway in the thirteen chapters I've sent you.")
Martin's initial idea features a much smaller cast of characters, but still includes the Lannisters, Starks, Dothrakis, and Targaryens. From there, storylines get pretty radically different. Sansa, for example, marries King Joffrey, bears his son, and, Martin writes, "when the crunch comes she will choose her husband and child over her parents and siblings, a choice she will later bitterly rue."
Arya, meanwhile, falls in love with her half-brother Jon Snow, a man of the Night's Watch who is sworn to celibacy. "Their passion will continue to torment Jon and Arya throughout the trilogy," Martin writes. But this love affair gets even more twisted: Tyrion Lannister falls in love with Arya, who only has eyes for Jon; this leads to "a deadly rivalry between Tyrion and Jon Snow." At one point, Catelyn, Arya, and Bran go North, beyond the wall, and are captured by Mance Rayder. There, they "get a dreadful glimpse of the inhuman others as they attack the wildling encampment."
Across the Narrow Sea, Daenerys Targaryen still marries Khal Drogo, who has no interest in capturing the throne of the Seven Kingdoms and kills her brother Viserys when he refuses to let it go. Presumably, Viserys is less of a jerk in this version than in the published book, because Daenerys actually kills Khal Drogo to avenge him. Then, she flees "with a trusted friend into the wilderness beyond Vaes Dothrak," where she discovers a clutch of dragon eggs.
One thing that hasn't changed between the outline and now is Martin's willingness to kill off beloved characters. "I want the reader to feel that no one is ever completely safe, not even the characters who seem to be heroes," he wrote. "The suspense always ratchets up a notch when you know that any character can die at any time."
You can read more about it at WinterIsComing.net, which has tons of other interesting and weird details.
Updated for 2019.