Edward's initial strategy was to ally with Flanders and the princes of the Empire. The alliances were costly and not very productive. While on a truce the French and English kings intervened in the War of the Breton Succession. In 1346, Edward invaded France and pillaged the countryside rather than attempt to hold territory. French forces led by Philip VI confronted Edward III at the Battle of Crécy, which resulted in a devastating and humiliating defeat for the French. Despite this, the most that Edward could make out of his victory was the capture of Calais.