Lannister
Lannister was the last direct descendant of the kings of the Rock who ruled before the Targaryens came to Westeros, the only daughter of Gerold III Lannister.
Her marriage to a knight named Joffrey Lydden would decide who inherited the throne of Casterly Rock once her father died without a son.
Chapter 1
The queen who gave a house its name
Books only
While still a princess of the Kingdom of the Rock, Lannister married Ser Joffrey Lydden. When her father, King Gerold III, died without leaving a son to succeed him, it fell to a council of the court to choose who would rule Casterly Rock next.
The choice fell on her husband. Ser Joffrey took the crown as King of the Rock and changed his surname to Lannister, becoming the first Andal to sit on the throne of Casterly Rock. Through her marriage, the blood of the old kings of the Rock joined the house that would carry its name for centuries to come.