|Title||Lady of Casterly Rock|
|Spouse||Lord Lyman Lannister|
Jocasta's husband, Lord Lyman Lannister, protected Prince Aegon and Princess Rhaena Targaryen during the early years of the reign of King Maegor I Targaryen, extending them guest right. During their stay at Casterly Rock, Jocasta was the first to recognize that Rhaena was pregnant.
In early 49 AC, Jocasta and her husband attended the small wedding of Rhaena to Androw Farman. After Rhaena was exiled from Fair Isle in early 50 AC, Jocasta and Lyman welcomed them to Casterly Rock, staging a lavish feast in their honor. During the time Rhaena and her court remained at Casterly Rock, Jocasta suggested to Rhaena that one of Rhaena's dragon eggs would make a fine gift to House Lannister, to thank the Lannisters for providing them with a place to stay. Rhaena was not responsive to the suggestion, and departed from the Rock shortly after.