Born around 230, Princess Rhaelle Targaryen was the youngest daughter of Aegon V Targaryen and his wife Betha Nerbosc. She was the niece of Maester Aemon (whom she called "Uncle Maester").
She was married to Ormund Baratheon, heir of House Baratheon, and had at least one son, Steffon. She is therefore the grandmother of Robert, Stannis and Renly Baratheon.
During the reign of Aegon V TargaryenWhile his older brother, Prince Duncan Targaryen, was promised to the daughter of Lord Lyonel Baratheon, he broke off the engagement to marry Jenny of Old Stone for love, which led to a major crisis between the crown and House Baratheon.
Lord Lyonel Baratheon enters into rebellion against the Iron Throne, even taking the title of King of the Storm, which was held by the Durrandons before the Conquest.
A judgment of the gods is called to resolve the conflict, and pits Lord Lyonel Baratheon against Ser Duncan the Great, knight of the Kingsguard. The latter defeats Lord Lyonel, and King Aegon V offers the hand of his daughter, Princess Rhaelle, to Lord Lyonel's heir son, Ormund Baratheon.