A major revelation about Jon Snow’s parentage was revealed on Game of Thrones last night — and almost nobody noticed.

In a particularly sneaky piece of story work, Game of Thrones 7×05 slipped a critical detail about Rhaegar Targaryen into the narrative.

Rhaegar is widely presumed to be Jon Snow’s real father, especially after season 6 of Game of Thrones confirmed that Jon’s mother was Lyanna Stark. But the question of Jon’s legitimacy persisted; Rhaegar Targaryen was married to Elia Martell and had two children with her, so — it seemed — Jon would still have been born a bastard.

But as the plucky and curious Gilly poured over Maester Maynard’s long, dull treatise recording windows, annulments, and poops, she uncovered a very important piece of the puzzle.

“Maynard says here that he issued an annulment for a Prince Rhaegar,” Gilly reads, “And remarried him to someone else at the same time, in a secret ceremony in Dorne.”

As sure as winter is coming, that “someone else” is almost definitely Lyanna Stark.

This revelation has a multitude of consequences for the narrative. Jon is not only a Targaryen, he is a legitimate Targaryen — which would likely place him above Dany in the succession. Incidentally, the annulment and marriage would also delegitimize Rhaegar’s other children, adding further insult to the neutralized Dornish contingent.

And on a personal level, news of Rhaegar and Lyanna’s marriage makes it very likely that Lyanna wed Rhaegar of her own free will. She was not kidnapped, she was not raped, and the entire war of Robert’s Rebellion was fought for no greater reason than petty jealousy.

Of course, the question remains as to how — or even if — this news will be made known to Jon and other characters. The importance of Gilly’s discovery was utterly lost on Sam, who lamented the recording of this apparently useless information “while the secret to defeating the Night King is probably sitting on some dusty shelf somewhere, completely ignored.”

That’s what we in the business call irony.

It is also unclear whether or not Sam and Gilly packed Maester Maynard’s volume with them when they left the Citadel. If so, the critical news may eventually find its way into the hands of those who can appreciate its importance.

But if Gilly left the book behind, this piece of Jon’s puzzle may be destined to exist just for us viewers. Jon Snow may never know that his parents loved each other, that they married, and that in doing so, they bequeathed him a throne he never imagined sitting.

Of course, the information could sneak through another way — via Bran and his magical tree visions, for example. But we’ll have to wait and see just how mean Game of Thrones decides to be with this all-important mystery. Will this news blossom into relevance for the story? Or will the fans be left brimming with knowledge, as Jon continues on his unknowing way?

Only time (and perhaps Gilly) will tell.