Viserys II Targaryen, King of the Seven Kingdoms

From Asoiaf

Viserys II of House Targaryen, King of the Seven Kingdoms (reigned 171 AL - 172 AL), was the fourth son of Aegon III Targaryen, King of the Seven Kingdoms.

Viserys succeeded his older brother Baelor I on the throne.

He had two sons, Aegon IV and Aemon the Dragonknight.

On his death Aegon IV became king.