Battle of Bouvines

On July 27, 1214, Philip II Augustus confronted the coalition army of Otto IV near Bouvines, strong of Flemings, Brabançons and English knights. The battle begins with the attack of the imperial left wing on the French communal militias; after fierce fighting, the counter-charge of the Capetian chivalry pushed the imperial center. Otto IV fled, while Ferrand of Flanders, Renaud of Boulogne and William Longsword were captured, sealing the Capetian victory.

Since 1212, John Lackland has been trying to overthrow Philip Augustus by coordinating a two-front offensive: he himself lands in Poitou, while Otto IV comes down from Flanders with the support of the rebel princes. After the English failure at Roche-aux-Moines (June 1214), Philippe marched north to prevent the junction of his enemies. He had around seven thousand men – royal knights, sergeants on foot, militias from Paris, Soissons and Amiens – and chose to fight on a Sunday in order to surprise the adversary who thought he would avoid battle.

Philip deploys his army in three 'battles': Robert of Dreux on the left with the communal militias, the king in the center with the Oriflamme banner, and the Duke of Burgundy Eudes III on the right. The sergeants on foot formed a wall of lances to absorb the Flemish charge, while the knights, grouped in reserves, launched targeted counter-charges. The Capetian center fixes Otton thanks to the sergeants of the Paris provost; an enveloping maneuver led by William des Roches and Thomas de Saint-Valery captured the imperial standards, forcing Otto's retreat and flight.

The capture of Otto's main allies disintegrated the coalition: Ferrand remained a prisoner for twelve years, Renaud of Boulogne died in captivity and the emperor, discredited, was deposed in favor of Frederick II. John Lackland, deprived of continental support, had to accept in 1215 the Magna Carta imposed by his barons. In France, Philip II Augustus confiscated the rebel fiefs, strengthened the royal administration (bailiffs and provosts) and became the undisputed arbiter of the Capetian kingdom.