The Anglo-French War (in French: Guerre de Guyenne) was a conflict between 1294–98 and 1300-03 revolved around Gascony. The Treaty of Paris (1303) ended the conflict. Serious conflict was precipitated in 1293, when clashes between French and English seamen caused Philip IV to summon his vassal to Parlement. When Gascon castles occupied by the French as part of the settlement were not returned to the English on schedule, Edward renounced his homage and prepared to fight for Aquitaine. The war that ensued (1294–1303) went in favour of Philip the Fair, whose armies thrust deep into Gascony. Edward I retaliated by allying with Flanders and other northern princes. His dangerous campaign, concerted with the Count of Flanders in 1297, met defeat from a French force led by Robert II, Count of Arto