Queen Aemma Arryn is an unseen character in Game of Thrones. She is long dead by the time of the series. She was a Queen Consort of the House Targaryen dynasty. She is only mentioned in Histories & Lore.
At some point, she married the much older Viserys I Targaryen, and gave him a daughter, Rhaenyra Targaryen. Aemma later died before she could bore him a son. Viserys later married Alicent Hightower, who gave him two sons and a daughter.
In the Books Edit
Aemma was the daughter of Lord Rodrik Arryn and his wife, Princess Daella Targaryen, herself the daughter of King Jaehaerys I Targaryen and his sister-wife Alysanne Targaryen. Aemma married Prince Viserys Targaryen, her cousin, in 93 AC. Upon her grandfather's death, Aemma became the queen consort of Viserys, who had been chosen as heir to the throne during the Great Council in 101 AC.
Aemma became pregnant multiple times in the early years of her marriage. She suffered multiple miscarriages, and gave birth to a son who eventually died in the cradle. In 97 AC, Aemma gave birth to a healthy daughter, Princess Rhaenyra. Aemma and Viserys both adored their only living child.
In early 105 AC, Aemma became pregnant once more. Late in the year, she gave birth to a son, Prince Baelon Targaryen. Aemma died during the birth, and her son died a day later.