Battle of Soindres (Mantes)

On August 17, 1188, taking advantage of a truce broken by Henry II, an Anglo-Norman column set fire to the suburbs of Mantes. Philip II urgently gathered royal knights and urban militias, blocked the road to Soindres and, after a charge of his heavy cavalry, pushed the looters back towards the Seine where many of them drowned. The English ride is dispersed and the loot abandoned.

After Hattin, Pope Clement III tried to impose peace between Capetians and Plantagenets to prepare for the third crusade. Henry II, however, relaunched the war in Normandy in the spring of 1188, increasing the number of raids against the French Vexin. Mantes, a lock on the Seine, is defended by merchant militias and a few knights of the king; Philippe is staying in Paris but can quickly reach the area thanks to the relay network established on the right bank.

Philippe combines rapid reconnaissance and use of the terrain: sergeants on foot establish barricades in the hedges of Soindres to fix the Anglo-Normans, while the cavalry charges in two waves on the narrowed road. The archers of Mantes fired from the orchards to disarm the raiders, preventing any reformation and pushing the fugitives towards the marshes on the banks of the Seine.

The victory at Soindres reestablishes Capetian authority in Vexin and proves the effectiveness of the recently established communal militias. Henry II, faced with desertions and the indiscipline of his mercenaries, accepted a new truce the following year; he died shortly afterwards, leaving the English crown to Richard. The success strengthens Philip's image as defender of the kingdom and facilitates the raising of subsidies for the crusade.