Prince Jacaerys Velaryon is the eldest child and heir of Princess Rhaenyra Targaryen and her first husband, Laenor Velaryon. He is the only one of her children with a confirmed father as he was conceived prior to her marriage to Aemon Targaryen. Given his parents' similar features, his step-grandmother, Alicent Hightower, began the rumor that he was a bastard to destabilize his mother's claim to the throne. Jacaerys is a dragonrider to the dragon Vermax.
During the Dance of the Dragons, Jacaerys travels to Winterfell to gain the support of the North. While there, he meets and falls in love with Sara Stark, the young daughter of Cregan Stark. He signs the Pact of Ice and Fire to secure Northern support and then marries Sara. The two are wed, and she falls pregnant with a pair of twins. Unfortunately, Jace dies before meeting his twin daughters.