The Fan Theory You Need To Know For This Week’s Game of Thrones Episode

It takes only 30 seconds of footage or a leaked production shot to send Game of Thrones viewers into a tizzy of wild theorizing. In fact, it seems as if a new fan theory sprouts up every week. It's hard to know what to take seriously, and what to write off as wishful thinking. But there are a few fan theories that have been around for years — 20 years, in this case. One of the longest-standing, most credible, and widely believed fan theories was actually born by the earliest GoT readers in 1996, when George R.R. Martin published the very first book in the series, A Game of Thrones. Now, all signs indicate that this particular theory, about our boy Jon Snow, is about to be addressed in Sunday night's episode. It's a big one that pieces together a lot of background information and book-only material, and you're going to want to know the 4-1-1 beforehand. [SPOILER ALERT, duh].

The theory is commonly referred to as "R + L = J." Now, we and Jon have been led to believe that he is the bastard son of Ned Stark (RIP) and an unknown woman. But, according to this fan theory, Rhaegar Targaryen ("R") and Ned's little sister Lyanna Stark ("L") are the real parents of Jon Snow ("J"). Here's how it breaks down:

- Who is Rhaegar Targaryen, you ask? He is the son of the Mad King, Aerys II Targaryen, and therefore the brother of Viserys (dead) and Daenerys. The Mad King, we know, was overthrown by Robert Baratheon (also dead).

- That rebellion was kicked off (at least in part) by Lyanna Stark's love affair with prince Rhaegar Targaryen, because she was betrothed to Robert. (Nonessential info: Making this love triangle a love rhombus is the fact that Rhaegar was married to Elia Martell.)

- Illicit lovers Lyanna and Rhaegar spent the beginning of the war holed up in the Tower of Joy in Dorne. Then Rhaegar went to battle and met his death at Robert's hand.

- After the war ended, Ned took a few of his men to the Tower of Joy in Dorne to rescue his sister Lyanna. They encountered several guards who they fought in a battle outside the Tower of Joy. This particular battle scene looks to play out in a scene from this March teaser (above) and the episode three preview below, beginning at 0:22. "Now it begins" and "Now it ends" are uttered, borrowed from that scene in the book. That sure looks like a young Ned Stark to us! Bran and the Three-eyed Raven are looking on, probably in one of Bran's visions.

- But when they found Lyanna in the tower, she was lying in a pool of blood. Clinging to life, her last words to Ned were "Promise me..." Promise you what, Lyanna?! This is where it all comes together. Fans speculate that Lyanna was actually dying during childbirth: The love child of hers and Prince Rhaegar Targaryen's. She was asking her brother Ned to promise her he'd take the child back to Winterfell and raise him as his own bastard son: Jon Snow. (Otherwise, Robert Baratheon — who murdered members of Rhaegar's family in vengeance — would likely kill his bae's illegitimate child, too, which is why guards were protecting Lyanna.)

And here's why we are kind of in love with this theory:

- It never sat right with us that Ned Stark, the most morally upright man in all of Westeros, cheated on the love of his life, Catelyn.

- There is supporting textual evidence that Ned is lying about being Jon's father throughout the books. He forgets to list Jon as one of his children; he declines to slaughter other Targaryen children; and, at one point, it's said that he has a dangerous but necessary secret that he's been lying about for 14 years (at which point Jon is 14 years old). There are also a bunch of references to a "blue flower" — a symbol of Lyanna — in connection to Jon, which makes sense if she's his mother.

- It makes Jon possibly the most important and powerful individual in Game of Thrones. With both Stark and Targaryen blood, he would be the greatest contender for the Iron Throne. Unfortunately, unless his parents Lyanna and Rhaegar were secretly married, he is still technically a bastard despite his formidable bloodline. Also, remember: Jon doesn't know any of this, and as far as we know, no one alive knows the truth either.