After decades of conflicts with the House of Plantagenet, Philip succeeded in putting an end to the Angevin Empire by defeating a coalition of his rivals at the Battle of Bouvines in 1214. This victory would have a lasting impact on western European politics: the authority of the French king became unchallenged, while the English King John was forced by his barons to assent to Magna Carta and deal with a rebellion against him aided by Philip's son Louis, the First Barons' War. The military actions surrounding the Albigensian Crusade helped prepare the expansion of France southward. Philip did not participate directly in these actions, but he allowed his vassals and knights to help carry them out.