Prince Rhaegar Targaryen, the last Prince of Dragonstone, was the eldest son and heir to King Aerys II Targaryen, the Mad King. He was the older brother of Viserys and Daenerys Targaryen and the husband of Elia Martell, with whom he had two children: Rhaenys and Aegon Targaryen.

Secretly, however, Rhaegar annulled his marriage with Elia and married Lyanna Stark in Dorne. Rhaegar's alleged "abduction" of Lyanna sparked Robert's Rebellion as Lyanna was betrothed to Robert Baratheon. Robert killed Rhaegar at the climactic Battle of the Trident, bringing on the deposition of the Targaryen dynasty. Lyanna's brother Eddard Stark found her soon afterward at the Tower of Joy in Dorne, where she was dying in childbirth. She had just given birth to her son with Rhaegar and begged her brother to keep her baby safe. To protect the child from Robert and others who sought the absolute destruction of House Targaryen, Eddard claimed his sister's son as his own bastard child whom he had fathered during the war: Jon Snow.