Battle of Verneuil

On August 17, 1179, Louis, son of Philip II Augustus, led a raid against Verneuil to cut Plantagenet communications. While he tried to surprise the place, the Anglo-Norman knights suddenly came out and, reinforced by William the Marshal, took the Capetian vanguard from the flank. The French army is disintegrating; Louis is unhorsed and taken prisoner before being released for ransom.

The Cold War between Philip Augustus and Henry II intensified after the revolt of Henry's sons. Philippe entrusts his heir with an expedition to Normandy to increase his prestige. The Capetians, unfamiliar with the Norman bocage, relied on local allies who lured them towards Verneuil without prior reconnaissance, while Henry II reinforced the garrison of seasoned knights.

The Capetians advance in column along the Avre; the French cavalry engages against the Porte de Verneuil without waiting for the infantry. William the Marshal and the Anglo-Norman sergeants came out through a postern, struck the open flank and pushed the knights back towards marshy ground where their mounts got bogged down. A Plantagenet counterattack cuts off the retreat, allowing the capture of Louis and several French banners.

The capture of the prince reveals the fragility of the Capetian military apparatus: Philippe must pay a large ransom and multiply the oaths of loyalty to avoid defections. The episode triggered a reform of the royal host – creation of permanent companies and better discipline – which would bear fruit in the campaigns of 1180-1186. Louis learned his lesson and then favored the use of urban militias and methodical sieges.