For awhile now, there's been a theory floating around Game of Thrones forums and discussion boards that centers around the notion that Jon Snow isn't entirely who he appears to be. Up to this point, both viewers of the television show and readers of George R.R. Martin's A Song of Ice and Fire know Snow as Ned Stark's bastard, a more-than-competent member of the Night's Watch and a knower of nothing. But according to this theory, dubbed "R+L=J" by its proponents and endorsed in recent weeks by no less than Ned Stark (Sean Bean) himself, Snow is much more.
R+L=J suggests that Snow is not, in fact, the bastard son of Ned Stark. Rather, he's the love-child of Ned's sister, Lyanna (the betrothed of Robert Baratheon) and her captor/suitor Rhaegar Targaryen, (son and heir of the mad king, Aeyrs II Targaryen). There are many little clues sprinkled throughout the series to support this theory, but it didn't start gaining mainstream traction until earlier this summer when Bean apparently confirmed it.
Now, it seems, another person loosely tied to the Game of Thrones universe is hinting at its veracity: George R.R. Martin. Here's what the author had to say at the Edinburgh International Book Festival:
"I want to surprise and delight my reader and take them in directions they didn't see coming. But I can't change the plans... So many readers were reading the books with so much attention that they were throwing up some theories and while some of those theories were amusing bulls**t and creative, some of the theories are right. At least one or two readers had put together the extremely subtle and obscure clues that I'd planted in the books and came to the right solution... So what do I do then? Do I change it?! I wrestled with that issue and I came to the conclusion that changing it would be a disaster, because the clues were there. You can't do that, so I'm just going to go ahead. Some of my readers who don't read the [online fan] boards, which thankfully there are hundreds of thousands of them, will still be surprised and other readers will say: 'See, I said that four years ago, I'm smarter than you guys'."
It's possible that Martin could be talking about an entirely different major twist — but R+L=J would be huge for the Game of Thrones universe and has certainly been the most prominent theory in recent months.
As for what this revelation would mean for Westeros, that's less clear. Though Snow's Stark-Targaryen parentage would be an impressive pedigree, it wouldn't change his status as either a bastard or a member of the Night's Watch (and as such, has resolved to "hold no lands" and "wear no crowns"). That said, virtually every claim to the Iron Throne is contested and convoluted at this point. Maybe Snow could throw his cloak into the red keep after all.