Lady Aemma Arryn was the queen consort and first wife of King Viserys I Targaryen, and a granddaughter of King Jaehaerys I Targaryen and his sister-wife, Queen Alysanne Targaryen. She 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. She died giving birth to a son, Prince Baelon Targaryen, who died a day later.
Alicent Hightower was the second wife to King Viserys I Targaryen, and a member of House Hightower. After Viserys’ first wife Aemma Arryn passed, she became his second wife. Originally, Queen Alicent had a good relationship with her stepdaughter, Princess Rhaenyra. But when Alicent gave birth to a son, Prince Aegon, a daughter, Princess Helaena, and another son, Prince Aemond, in rapid succession, and Rhaenyra remained Viserys’ heir, those feelings started to change. Both women wanted to be the first lady of the realm, but there could only be one.