Princess Rhaenys Targaryen
From Asoiaf
Princess Rhaenys of House Targaryen was the daughter of Prince Rhaegar Targaryen and Princess Elia of House Martell.
Rhaegar was slain by Robert Baratheon on the Trident.
Rhaenys was slain together with her mother and brother Aegon during the Sack of King's Landing. She was then a young girl.