Quick answer: Robert Baratheon’s grandmother was a Targaryen princess — Rhaelle Targaryen, daughter of King Aegon V (Egg himself). That makes Robert the great-grandson of a Targaryen king, second cousin to Rhaegar (yes, the man he killed), and — this is the part that stings — a rebel whose claim to the throne rested on the very blood he was busy spilling. See it mapped on the family tree.
The Exact Connection: One Grandmother, Whole Rebellion
Here’s the path, and it’s shorter than you think:
Aegon V "Egg" (r. 233–259 AC)
│
┌───────────┴───────────┐
Jaehaerys II Rhaelle Targaryen ═ Ormund Baratheon
│ │
Aerys II Steffon Baratheon
"the Mad King" │
│ ┌─────────┼─────────┐
Rhaegar ROBERT Stannis RenlyThree hops: Egg → Rhaelle → Steffon → Robert. That’s it. Robert’s father Steffon was the Mad King’s first cousin, which makes Robert and Rhaegar second cousins — close enough that when Robert’s warhammer found Rhaegar’s chest at the Trident, the family tree technically logged it as an internal dispute.
Wait, So Robert Had a Claim?
Oh, he absolutely had a claim, and it’s one of the great open secrets of the rebellion. When the fighting ended in 283 AC, the rebels faced an awkward question: why Robert for king? Ned Stark had the honor, Jon Arryn had the armies, and Robert had… a warhammer and a grudge?
No — Robert had grandmother Rhaelle. The maesters could stand in the throne room and announce, with straight faces, that Robert Baratheon was the closest blood relative of the old dynasty once the Mad King’s line was disqualified. The blood of the dragon, flowing in the usurper. It was the legal fig leaf that made the whole regime change look like succession instead of conquest.
Was it also conquest? Completely. But in Westeros, conquest goes down easier with a family tree attached.
The Broken Betrothal Behind It All
And here’s the layer nobody expects, because the Baratheon-Targaryen link wasn’t planned as dynastic strategy — it was an apology.
Aegon V’s eldest son, Duncan the Small (the Prince of Dragonflies — yes, that Duncan’s namesake), was betrothed to the daughter of Lord Lyonel Baratheon, the “Laughing Storm.” Then Duncan fell in love with a commoner, Jenny of Oldstones, and broke the betrothal to marry her.
Lyonel Baratheon’s response was to renounce his fealty and declare himself Storm King. An actual, if brief, Baratheon rebellion, decades before Robert’s. The crown patched it up the traditional way: a replacement marriage. Princess Rhaelle, Egg’s daughter, was betrothed to Lyonel’s heir Ormund — and their son Steffon was Robert’s father.
So the entire chain of events runs: broken betrothal → patched-up marriage → Steffon → Robert → rebellion → the Baratheon dynasty exists because a Targaryen prince followed his heart. This family cannot catch its own irony even when it’s swinging at them.
Bonus Layer: The Baratheons May Be Dragonseed Anyway
One more for the road. House Baratheon’s founder, Orys Baratheon, was Aegon the Conqueror’s closest friend and commander — and was widely rumored to be Aegon’s bastard half-brother. If the rumor’s true, the Baratheons carried Valyrian blood from the day the house was founded, three hundred years before Rhaelle.
Meaning: whether through Orys at the start or Rhaelle near the end, the storm lords and the dragonlords were never really separate families. They were one long, entangled family tree that occasionally paused to have wars with itself. (Which, incidentally, is also why the bloodline never truly ends.)
FAQ
Was Robert Baratheon part Targaryen?
Yes — his grandmother Rhaelle Targaryen was the daughter of King Aegon V, making Robert one-eighth Targaryen by recent descent, and possibly more if the Orys Baratheon bastard rumors are true.
How are Robert and Rhaegar related?
Second cousins. Robert’s father Steffon and Rhaegar’s father Aerys II were first cousins — Rhaelle and Jaehaerys II were brother and sister.
Why did Robert become king instead of Ned Stark?
Partly charisma and conquest — but officially, his Targaryen grandmother gave him the strongest legal claim among the rebel leaders. The blood of the dragon legitimized the rebellion that destroyed the dragons.
Is Gendry related to the Targaryens?
Yes — as Robert’s son, Gendry carries Rhaelle Targaryen’s blood. After Daenerys legitimized him, the show’s ending leaves House Baratheon as the most prominent family with Targaryen blood still in it.
Who was Rhaelle Targaryen?
Daughter of Aegon V and sister of Jaehaerys II, married to Ormund Baratheon to settle the crisis after Duncan the Small broke his Baratheon betrothal for Jenny of Oldstones. Robert, Stannis, and Renly’s grandmother.