Only child of Prince Aemon Targaryen, the eldest son of Jaehaerys I, and Lady Jocelyn Baratheon of Storm's End. Rhaenys was born in 74 AC and raised in the certainty that her father would one day be king and that she, his heir, would follow him. When Prince Aemon was killed by a stray crossbow bolt on Tarth in 92 AC, King Jaehaerys passed her over and named his second son Baelon his heir instead, the small council reasoning that the realm would not abide a queen. Nine years later, at the Great Council of 101 AC summoned to settle the succession after Baelon's death, the lords passed her over a second time, choosing her cousin Viserys to inherit and rejecting her son Laenor for no greater fault than his mother's sex. She never forgave it, and the byname the Queen Who Never Was followed her to her grave.
At sixteen she had been wed to her cousin Corlys Velaryon, the great Lord of the Tides and master of the largest fleet in Westeros, and at Driftmark she made a court that rivalled King's Landing. She gave the Sea Snake two children, Laena born in 92 AC and Laenor in 93 AC, both dragonriders, both wedded into the line of succession, and both lost before their mother. After Laenor was killed at Spicetown and Laena died of childbed in 120 AC, Rhaenys turned the whole of her remaining hopes on her granddaughters Baela and Rhaena, daughters of Laena by Prince Daemon, and on the cause of her uncle Viserys's chosen heir Rhaenyra.
In the dragon called Meleys the Red Queen she had ridden the oldest she-dragon of the realm since she was a girl, and when Viserys died she went to war on Rhaenyra's side. At the green coronation in the Dragonpit she flew Meleys up through the dome itself so the Hightowers would see her colours and pause; she could have burned half the council, and chose not to. She fell at Rook's Rest in late 129 AC, lured into the air alone by Lord Criston Cole's bait and ambushed there by Aegon II on Sunfyre and Prince Aemond on Vhagar. Meleys broke Sunfyre's wing and tore his neck before the older Vhagar bore her to the ground, and the Red Queen and her rider were crushed together upon the king's own ridgeline. Aegon was hauled out broken from the burning wreck and was never the same king after; the black party never replaced her at table or in the air.