- "To her credit, Rhaenys didn't flee."
- ―- Viserys Targaryen
Rhaenys Targaryen was the granddaughter of Jaehaerys I Targaryen, and the sister of Viserys I Targaryen and Daemon Targaryen. Her father died at some point, predeceasing her grandfather. Upon her grandfather's death, her brother Viserys I Targaryen ascended the throne. She later married Corlys Velaryon, and the two had at least one son, Laenor Velaryon, who would later marry Rhaenys's niece Rhaenyra Targaryen. Because the Lord of Driftmark is sworn to the Princess of Dragonstone, and the fact that their son was married to her, Corlys and Rhaenys presumably lived on Dragonstone. Rhaenyra would give Rhaenys three grandsons: Jacaerys, Lucerys, and Joffrey. When Laenor died, Rhaenyra married her uncle and Rhaenys's brother Daemon and had two more sons by him, Aegon and Viserys.
When her father Viserys died, Rhaenyra was expected to ascend the Iron Throne, since her father did not change the succession when he had a son. However, Aegon II Targaryen was crowned King in the Dragonpit, at bequest of Rhaenys' sister-in-law Alicent Hightower. The war between brother and sister would be known as the Dance of the Dragons. With Aegon's own Small Council in King's Landing, Rhaenys sat on Rhaenyra's, along with her husband, who was Hand of the Queen.
When Rook's Rest was attacked by Ser Criston Cole and the Greens, as Aegon II's supporters were called, Rhaenyra sent her aunt to burn the army and save the fort. Mounted on her dragon, Meleys, Rhaenys unexpectedly turned up at Rook's Rest and laid waste to the army, incinerating them, which she enjoyed. However, Rhaenys was flying into a trap. Her nephew Aemond Targaryen confronted her on his monstrous dragon Vhagar, the last of the original three Targaryen dragons along with the King himself, on his magnificent dragon Sunfyre. Despite being outnumbered, Rhaenys didn't flee. Meleys's flame faced Vhagar's and Sunfyre's, until it looked like that there was a second sun in the sky. By the time the fight was over, Aemond and Vhagar were the only ones uninjured, whilst Aegon had to have a constant dose of Milk of the poppy to survive and Sunfrye (who lay on top of Aegon) was wounded, and a wing almost completely torn off. It was crippled and would never fly again. Meleys had been to "torn to shreds" and Rhaenys was just ash and bone.
In the books
Great Council of 101
Princess Rhaenys was the daughter of Jocelyn Baratheon and Prince Aemon Targaryen, making her a cousin rather than sister to Viserys I. Rhaenys and the late Lord Boremund Baratheon had always been the staunchest of friends.
After the death of Prince Aemon in 92 AC, the Old King, Jaehaerys I Targaryen, chose his next son Baelon rather than Rhaenys as his heir.
The annals of the Great Council of 101 after Baelon's death record that the lords assembled had favored the male claimant, Viserys, Baelon's son, over the female - one of which was Rhaenys - by twenty to one, but there had been dissenters.
House Baratheon had always been a staunch supporter of the claims of Princess Rhaenys and her children. The Starks of Winterfell had spoken for Rhaenys at Harrenhal, as had Lord Stark's bannermen, House Dustin of Barrowton and House Manderly of White Harbour.
The Dance of the Dragons
Princess Rhaenys sat on the black council of Queen Rhaenyra Targaryen. When the Velaryon fleet closed off the Gullet, sailing forth from Dragonstone and Driftmark to block all shipping for Blackwater Bay, the black council's plan was for Rhaenys to fly overhead to keep their foes from attacking their ships with dragons.
Nine days after Lord Staunton dispatched a plea for help, the dragon Meleys appeared above Rook's Rest. On her back, in steel and copper armor that flashed in the sun, rode Rhaenys Targaryen.
As Rhaenys attacked the soldiers of Ser Criston Cole, King Aegon II Targaryen upon Sunfyre and Prince Aemond Targaryen upon Vhagar appeared in the skies. Criston had sprung a trap and Rhaenys had snatched the bait.
Princess Rhaenys made no attempt to flee, turning Meleys toward the foe. Against Vhagar alone, Meleys may have won but she stood little chance against both dragons. The dragons met violently a thousand feet above the ground and all three beasts went spinning to the earth. From the ashes, only Vhagar rose unharmed. A body believed to be Rhaenys Targaryen was later found beside the carcass of her dragon, but so blackened no one could be sure it was her.