First Blackfyre Rebellion

The First Blackfyre Rebellion was a significant war fought in Westeros between armies loyal to King Daeron II of the House Targaryen, defending his claim to the Iron Throne, and the rebel forces of his legitimized half-brother and rival, Daemon I Blackfyre.
Multiple battles took place in the Reach, the West, the riverlands and the Crownlands, culminating in the Battle of the Redgrass Field.
Daemon lost the war and his life, as did his two eldest sons, and the remaining Blackfyres went into exile.
The consequences of the rebellion are depicted in George R.R. Martin's The Sworn Sword.