Fans guessed Sunday's big shocker on 'Game of Thrones' over 2 decades ago

Warning: Spoilers ahead for "Game of Thrones" season six.

"Game of Thrones" just gave book readers a huge reason to celebrate. We're much closer to learning who Jon Snow's parents really are. The season six finale made it pretty clear that the newly crowned King in the North is likely the son of Lyanna Stark and Rhaegar Targaryen. That's a big deal because it would make Jon Snow the descendant of two of the greatest historically important houses in Westeros.

The reveal came through one of Bran's greenseeing visions. He traveled back to the Tower of Joy, first teased in season six episode three, where he watched as young Ned Stark discovered his sister Lyanna dying from a childbirth gone wrong. Bran watched as she begged Ned to protect her baby, because Lyanna knew Robert Baratheon would never let a Targaryen child live, and so Ned was forced to pretend the baby was his own bastard son.

While the reveal wasn't quite as direct as fans might have hoped, the edited shot from a baby's face straight to Jon Snow was the most confirmation fans have had yet.

Fans who have closely read George R.R. Martin's "A Song of Ice and Fire" series and spent time on fan forums like Westeros.org and the /r/asoiaf subreddit believed this theory (called "R + L = J") was a surefire thing. The earliest mentions Redditors have cataloged go back to 1998 on old chat logs and discussion boards. The fierce debate over the last two decades has cemented "R + L = J" into one of the most widely believed fan theories in the whole series.

Some people allege that Martin's editor, Anne Groell, figured out who Jon's real parents were when editing the first book of the series, "A Game of Thrones," before it was published in 1996. This would make sense, because many clues about Jon's real mother and father were given through Ned Stark's point-of-view chapters in "A Game of Thrones."

The fandom aside, learning Jon Snow's real parentage, as the show hinted at heavily in the finale, should have a huge impact on the series itself moving forward.

What this means for Jon Snow

First off, if the reveal is true it makes Snow the literal "Song of Ice and Fire," because of his ties to the northern Starks and the dragon-riding Targaryens. This also means he is technically Daenerys' nephew and Sansa's cousin. In terms of claims to the Iron Throne, it would depend upon whether or not Rhaegar actually married Lyanna, making Jon a legitimate royal child.

Rhaegar was already married to Elia Martell, but Targaryens have a history of taking multiple wives, so it is possible he married Lyanna too. If he did, Jon's claim to the Iron Throne is technically stronger than Daenerys' claim. He's the direct male descendant of the Mad King, whereas she is the sister of the former prince.

Furthermore, this reveal would really cement Jon as the focal point of the series. Daenerys, Tyrion, and Jon are often pointed to as the three main characters, but it's becoming more and more apparent that Jon has all the makings of an archetypal hero.

Jon Snow has quite the résumé in Westeros. He was born into royalty, but whisked away and given a different identity for his protection. Then he was raised among highborn and trained to fight despite his bastard status. He joined the Night's Watch, and became a double agent among the wildlings. Then he held Castle Black against the largest army of the wildlings the North has ever seen before being elected as the youngest Lord Commander the Night's Watch has had in centuries.

After brokering a peace with the wildlings, he was assassinated and then magically brought back to life by a red priestess. He then assembled a sparse but loyal army and bravely battled the Boltons, eventually defeating Ramsay and retaking his family's castle.

Jon owns a pet direwolf, one of the only two left known to mankind in Westeros. He carries an ancestral Valyrian steel sword - a weapon capable of killing White Walkers. Oh, and of course, Jon is one of three living people to ever fight a White Walker and survive.

Now he's been crowned the King in the North and will lead the inevitable war against the White Walkers.

Jon is clearly being set up as the opposite of Daenerys, the Mother of Dragons who represents fire and destruction. She is a conqueror, headed to Westeros to reclaim the seat of power her family held for centuries. Daenerys has heroic qualities and certainly has overcome a lot of adversity to get to where she is today, but Jon's lack of awareness about his past is the key difference here. He never meant to rule, but it might be his only path forward.

Rhaegar Targaryen and Lyanna Stark's union set a war in motion, the effects of which are the basis of the entire "Game of Thrones" series. Jon is the probable song of ice and fire, and his time has finally come. Now he just has to find out for himself.