'Game Of Thrones' R+L = J Theory
Can fans expect more R+L=J theory clues during "Game of Thrones" Season 5? HBO

With "Game of Thrones," chatter about R+L=J is as inevitable as the fact that winter is coming. The popular fan theory was nudged one step closer toward confirmation in "Game of Thrones," Season 5, episode 4, "Sons of the Harpy." Whether based on Littlefinger's knowing looks, Melisandre's behavior or Stannis Baratheon's comments, many people believe the theory embodies Westeros' worst-kept secret. Here are a few things to look for in future episodes that could further confirm the R+L=J theory.

Warning: "Game of Thrones" Season 5 spoilers and "A Song of Ice and Fire" discussion dead ahead.

The question about the identity of Jon Snow's mother has been hanging over the HBO television series since its first episode. We know he's believed to be Ned Stark's bastard, but the show has been pretty vague about potential contenders as his mother. Some have suggested a bar maid or a fling, but -- as Stannis noted in "Sons of the Harpy" -- that doesn't quite seem right. Ned's sense of honor cost him his life, so why would he just decide to step out on his wife Catelyn during Robert's Rebellion?

All the R+L=J stuff begins with the Tourney at Harrenhal, which was mentioned in the episode last week. That's where Prince Rhaegar Targaryen chose Lyanna Stark over his wife -- Elia Martell of Dorne -- as the Queen of Love and Beauty. Problem was, Lyanna was already set to marry Robert Baratheon. This encounter ultimately led to either the kidnapping of Lyanna by Rhaegar or the two running off together, depending on which side you believe. At the end of Robert's Rebellion, Ned travels to the Tower of Joy to rescue Lyanna, but the place is protected by three members of the Kingsguard. After the battle, Ned finds Lyanna in a pool of blood, and he makes a promise to his sister before she dies.

According to the R+L=J theory, Rhaegar and Lyanna are Jon Snow's parents -- and the promise Ned made was to protect the child. It appears "Game of Thrones" is working itself toward the confirmation of the theory. In the latest episode, Littlefinger had a bemused look on his face when Sansa said Rhaegar kidnapped and raped Lyanna. The Rhaegar that Ser Barristan Selmy knew seemed unlikely to commit such acts: The famed knight shared a story of how much the prince loved to play music for the people. And even Stannis chimed in about Ned's character and how unlikely it seemed for him to cheat on Catelyn.

While it was not quite as overt as the version in the "A Song of Ice and Fire" series of novels underlying the TV show, Daenerys Targaryen's vision in the House of the Undying lends itself well to the idea that Rhaegar and Lynna are Jon Snow's parents. According to readers of the novels, Daenerys has in them a vision that includes a glimpse of Rhaegar dying -- and one of the biggest R+L=J clues: A winter rose is seen growing in a wall of ice, which many believe is a reference to Jon Snow, who is currently at the Wall.

The TV series changed the visions in the House of the Undying in Season 2, but there's enough there to keep the theory alive. There's the burned-out ruin of the Red Keep in the snow and Daenerys' appearance at the Wall. Although there is no winter rose -- Lyanna's favorite flower -- there's still enough in the vision to point toward Jon Snow and the North being important to Daenerys.

One thing the show has not really covered is the "dragon has three heads" aspect of the visions. Daenerys has three dragons, and the Targaryens previously conquered Westeros by riding three dragons. Many readers believe Daenerys and Jon will ride two dragons, while the third rider is still unknown. Some conjecture it will be Tyrion Lannister, who could be revealed as a secret Targaryen; others speculate it will be Bran Stark.

"Game of Thrones" series co-creators David Benioff and D.B. Weiss, as well as novelist George R.R. Martin, are all well aware of the theory, but could they be pulling a fast one on viewers? We decided to ask a person who could know such a thing: Elio M. Garcia Jr., who runs Westeros.org with Linda Antonsson. The duo know pretty much everything there is to know about "A Song of Ice and Fire" -- even Martin and HBO consults with Garcia. He and Antonsson think the R+L=J theory is correct, based on the evidence in Martin's novels.

And fans expecting a little more Rhaegar in their lives may be out of luck. "Based on what we know, I would guess that only likely source of any more information concerning Rhaegar and Lyanna would be either passing remarks from characters such as Cersei, or perhaps likelier still from Melisandre," Garcia said. For readers, there's an important event involving Jon Snow that will likely happen at some point in "Game of Thrones" Season 5.

Of course, we're talking about his so-called death. Many readers quickly dismissed his apparent demise, and it'll be interesting to see how the show handles the scene. Melisandre could figure prominently in his death -- whether it's by bringing him back from the dead or engaging in some other type of sorcery -- and that could lead to another bit of confirmation in terms of the parenthood theory. "While Melisandre was not around in Westeros in the time period of Robert's Rebellion, she does have visions in her fires, and might well glimpse something relevant," Garcia explained.

So, when can fans expect to learn more about Jon Snow's parents and maybe Rhaegar and Lyanna? "For the most part, however, I suspect this past episode contains most of what they'll do touching on the events of the past. Season 6 -- especially when we have the return of Bran and the Three-Eyed Crow -- strikes me as the time that they'll provide much more depth on the matter," Garcia said. "Game of Thrones" Season 5 had the first flashback of the series, and Bran's ability could prove quite useful in clarifying just what happened to spark Robert's Rebellion.

"The writers have certainly shown themselves capable of discarding the books when they feel they have to, so I wouldn't put it past them to play on fan speculation while preparing to craft something very different. Only time will tell," Garcia said.