THE ASHES AND BLOOD. . .daemon targaryen

Before Viserys married Aemma and had Rhaenyra, he married a Stark woman who was different from the ladies of Kings Landing, which is why Viserys fell in love with Lyanna Stark. A year after their marriage, Lyanna died in childbirth. Amid mourning, Viserys Targaryen's firstborn daughter, Princess Daenerys of House Stark and Targaryen, took her first breath, later known as the Rose of the Realm and a woman before whom even the strongest men fell to their knees.
And when A Dance with Dragons begins, Daenerys vows to herself that she'd rather burn all the lands of Westeros than let her closest family be hurt.