Philip broke up the large Angevin Empire presided over by the crown of England and defeated a coalition of his rivals (German, Flemish and English) 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 sign the Magna Carta and deal with a rebellion against him aided by Philip, the First Barons' War.