|The title of this article is conjecture based on information revealed in the A Song of Ice and Fire novels and may be subject to change.
The Last Storm was a major battle in the Wars of Conquest. Aegon the Conqueror sent his commander Orys Baratheon, rumored to be his bastard half-brother, to conquer the Stormlands. The Stormlands were under the control of Argilac the Arrogant of House Durrendon, the Storm King.
Even though the massive walls of Storm's End provided protection against Baratheon's siege, Argilac decided to meet the invading armies in open battle after hearing about how Aegon Targaryen's dragon Balerion destroyed Harrenhal. Orys Baratheon and the Targaryen army were victorious and Argilac was killed.
As a reward for the victory, Aegon legitmized Orys Baratheon and named him Lord Paramount of the Stormlands. To cement his rule, Baratheon took Argilac's daughter, Argalia, as his wife. He also took both the sigil - a black stag on yellow - and words - "Ours is the Fury" - of House Durrendon as his own; thus, House Baratheon was founded.