The Battle of the Red Fork was a costly riverlands defeat that opened the way for the Lannister host to cross the river and continue its advance east. It unfolded alongside Prince Aemond Targaryen’s march on Harrenhal: while Aemond sought Prince Daemon Targaryen, the fighting on the Red Fork forced the riverlords to turn against a second advancing army.

Strategic setting

With Aegon II too badly injured to rule or fight, Aemond held the regency and command. He rejected advice to wait for reinforcements and marched toward Harrenhal with four thousand men, intending to confront his uncle. At the same time, Jason Lannister, Lord of Casterly Rock, brought the western host down from the hills toward the Red Fork and the heart of the riverlands. The riverlords had little choice but to turn and meet him.

Daemon was not caught unprepared. Friends in King’s Landing had passed word of his nephew’s plans to him before Aemond departed. When he learned that Aemond and Ser Criston Cole had left the city, Daemon welcomed the prospect; ravens then flew from Harrenhal. The two advances therefore converged on a region already bracing for battle, although the riverlords faced Jason’s army at the crossing while Aemond’s force continued toward Harrenhal.

Fighting at the crossing

Jason faced Petyr Piper, Lord of Pinkmaiden, and Tristan Vance, Lord of Wayfarer’s Rest. The westermen outnumbered their opponents, but the riverlords knew the ground. Three attempts to force the crossing were driven back. During the last, Pate of Longleaf, a grizzled squire, dealt Jason a mortal wound. Lord Piper later knighted him, giving him the name Longleaf the Lionslayer.

The riverlords’ success at the crossing did not hold. On the fourth Lannister attack, Adrian Tarbeck took command of the western host and changed the direction of the fight. He led a hundred picked knights upstream, where they removed their heavy armor and swam across the river. Circling behind Vance’s position, they struck the riverlords from the rear. The maneuver broke their ranks; as they fled, thousands of westermen crossed the Red Fork.

Outcome and significance

The battle turned on a contrast between local knowledge and numerical strength. The riverlords used the terrain to repel three assaults, but the Lannister host overcame their defense by changing its approach rather than simply repeating the frontal attack. Jason’s mortal wounding came before the decisive crossing, so his loss did not stop the westermen’s advance; Tarbeck’s command and flanking maneuver carried the engagement to victory.

The crossing gave the western army a route into the riverlands while Aemond’s host was also moving toward Harrenhal. The riverlords’ defeat thus formed part of a wider convergence of forces in the region, rather than a conflict isolated from the struggle for the Iron Throne. Its result was a tactical reversal: after holding the ford against three attacks, the riverlords were driven from their position and the westermen poured across the river.