On the occasion of the eight hundredth anniversary of the Battle of Bouvines (27 July, 1214), this essay examines its significance for the Capetian monarchy and its impact inside and outside the French kingdom. It argues that Philip II Augustus’s victory safeguarded the administrative reforms he had undertaken since 1190, boosted royal ideology, extended royal control in northwestern and central parts of France at the expense of Anglo-Angevin claims, cleared the path for the Albigensian crusade in the south, and eliminated Flemish and German threats from the north and east ; the battle’s ramifications for internal English, Flemish, and German affairs were far-reaching. The battle thus secured Capetian supremacy in France throughout the 13th century, but at the turn of the 14th Flanders and Gascony again posed intractable problems.