How did Varys know that Jon Snow was the rightful heir?

## The short version: Tyrion told him

The show gives a very clear answer in Season 8, Episode 4, “The Last of the Starks.” Varys hears that Jon Snow is really Rhaegar Targaryen and Lyanna Stark’s son from Tyrion Lannister. When Varys confronts Tyrion about the news, Tyrion works backward through the chain: Jon told Sansa and Arya, Sansa told Tyrion, and Tyrion told Varys. Varys confirms that this is exactly what happened.

So despite Varys being famous for his “little birds,” this was not one of his usual intelligence coups. He did not uncover a hidden birth record, find a secret witness, or have a spy inside Winterfell independently verify Jon’s identity. Tyrion simply brought him one of the most explosive pieces of political information in Westeros. That matters because Varys is acting on trust in Tyrion’s report, and on the evidence Tyrion says exists, rather than on proof Varys personally gathered.

## How Jon’s secret got to Sansa

Before Varys can learn anything, Jon first has to learn the truth himself. In Season 7, Episode 7, “The Dragon and the Wolf,” Bran Stark’s visions show that Rhaegar Targaryen and Lyanna Stark were secretly married. Samwell Tarly supplies the missing piece: he found a Citadel record saying Rhaegar’s marriage to Elia Martell was annulled.

Put together, the show treats those facts as proof that Jon was not Ned Stark’s illegitimate son. He was the legitimate son of Rhaegar and Lyanna, born Aegon Targaryen. In Season 8, Episode 1, “Winterfell,” Sam tells Jon what Bran has found and explains why it affects the succession. Rhaegar was the eldest son of the Mad King, Aerys II, while Daenerys was Rhaegar’s younger sister. If Jon is Rhaegar’s legitimate surviving son, he has the stronger Targaryen claim.

Jon eventually tells Sansa and Arya in the godswood. He asks them to swear secrecy first, but Sansa does not keep it.

## Why Sansa tells Tyrion

Sansa’s choice is the crucial leak. She knows Jon does not want the crown and has pledged himself to Daenerys, but she also deeply mistrusts Daenerys by this point. Sansa worries that Daenerys is too isolated, too hungry for power, and too willing to put the North second. Jon, meanwhile, is someone the Northern lords already love and someone Sansa believes would be easier to trust.

After the victory at Winterfell, Sansa tells Tyrion Jon’s real parentage. The scene is deliberately framed as Sansa making a political move, not accidentally blurting out family gossip. Tyrion understands immediately that the secret could change everything. He has been trying to hold Daenerys’s coalition together, but he is increasingly alarmed by her losses, grief, and anger. Once he knows Jon has a stronger blood claim and broad support, he sees why Sansa thinks the realm has another option.

Tyrion then tells Varys. As Varys later points out, once Tyrion has said it aloud, the secret is no longer realistically containable.

## Why Varys believes Jon should rule

Varys does not just collect the information and sit on it. He quickly treats Jon as a possible replacement for Daenerys. His old guiding line is that he serves “the realm,” not a particular royal family. Whether Varys always lives up to that claim is debatable, but it explains his reaction here: he thinks a ruler should be stable, capable, and accepted by the people.

To Varys, Jon has several advantages that Daenerys lacks by Season 8. Jon is respected in the North, has fought alongside ordinary people, inspires loyalty without demanding it, and is male in a society where that sadly makes his rule easier for many lords to accept. Varys also thinks Jon’s reluctance to rule is a good sign. A person who does not crave power may be less dangerous with it.

Daenerys, on the other hand, has just lost Jorah Mormont, a dragon, much of her army, and the sense of belonging she had with Jon. Varys sees her becoming isolated and suspicious. Jon’s identity gives him a political alternative at exactly the moment his faith in Daenerys collapses.

## The letters and Varys’s final move

By Season 8, Episode 5, “The Bells,” Varys has moved from private concern to open conspiracy. He writes letters saying that Jon Snow is the true heir to the Iron Throne. The episode does not identify every person receiving those letters, but the point is clear: Varys is trying to spread Jon’s parentage among the great houses and build support before Daenerys can stop it.

This is why Tyrion reports him to Daenerys. Tyrion still believes betrayal will lead to more bloodshed, while Varys believes doing nothing will leave the realm under a ruler he now considers dangerous. Their argument is one of the final breaks in their long friendship. Varys tells Tyrion that every time he backed the wrong ruler, ordinary people paid the price.

Daenerys has Varys executed at Dragonstone. His death comes before Jon ever chooses to challenge her publicly, and before the letters’ full impact can be shown. Still, Varys’s fears help set up the endgame: Daenerys burns King’s Landing, and Jon’s claim becomes even more politically important afterward.

## Was Jon unquestionably the rightful heir?

Within the TV show’s story, Jon has the better hereditary claim than Daenerys. Rhaegar was Aerys II’s elder son, and the series says Rhaegar legally ended his marriage to Elia and married Lyanna. That makes Jon Rhaegar’s legitimate son rather than a bastard, so Varys’s “true heir” language follows the show’s intended logic.

But there is an important in-universe catch: nobody holds a formal Westerosi hearing to prove any of it. The annulment record came from the Citadel, Bran’s part of the evidence comes from supernatural visions, and the marriage was secret. Most lords never meet Bran, see his visions, or inspect the documents themselves. Daenerys also has an army, a dragon, and an existing claim of her own.

So “rightful heir” is partly a legal argument and partly a political one. Varys believes Jon’s birth gives him the strongest claim, but the show never has a Great Council or court officially settle it. And this answer is TV canon only: the published A Song of Ice and Fire novels have not yet revealed Jon’s parentage to Varys in the same way.