Elia Martell

Elia Martell is an unseen character in Game of Thrones. She is deceased when the events of the series begin and is not expected to appear in the series.

Background
Princess Elia was the wife of Prince Rhaegar Targaryen. They had two children; a daughter Rhaenys and a son Aegon. She was born into House Martell in Dorne. Her marriage to Prince Rhaegar was arranged by King Aerys II Targaryen and considered an insult by Tywin Lannister, Aerys' Hand of the King, who had proposed his daughter Cersei as a bride for the Prince but was rejected. The marriage was one of the reasons Lord Tywin resigned his post as Hand.

When Robert's Rebellion erupted, Elia was kept in King's Landing by King Aerys to ensure the loyalty of House Martell during the conflict.

Rhaegar was killed during the fighting at the Battle of the Trident. Elia was raped and murdered by Ser Gregor Clegane during the Sack of King's Landing. Both of her children were also killed.

In the books
In A Song of Ice and Fire, Elia is also the wife of Rhaegar, and died with her children in the Sack of King's Landing. She was the sister of Princes Doran, the ruling Prince of Dorne, and Oberyn Martell.

During Robert's Rebellion, Gregor Clegane raped and killed Elia after bashing in her son's head, while his hands were still tainted with the infant's blood.

Tywin Lannister later admitted to Tyrion that there was no need to kill Elia because "by herself she was nothing" (in contrast to her children). The Mountain killed her simply because Tywin did not tell him to spare her. Tywin doubted if he had mentioned Elia at all, for he had many pressing concerns to worry about at that time, nor did he realize yet what kind of monster the Mountain was. On the other hand, he never punished Gregor for the rape and murder, because that would be an admission of indirect guilt on his part.