John meanwhile had called out the whole military force of the nation for an invasion of France. But all the barons of the North refused to follow him, and so great was the discontent of the English that he had mainly to depend on foreign mercenaries. He staked all his fortunes on the ensuing campaign, believing that if he could reconquer his lost continental dominions, he would afterwards win his way to complete control in England. His schemes were very far-reaching: Philip was to be attacked from north and south at once; while John was to land in Poitou and march on the Loire, a great confederacy of John's allies were to assail France from the north. This league was headed by John's nephew, Otho of Saxony, who claimed the title of emperor, but had been withstood in Germany by competitors whom Philip of France had supported. In revenge Otho gathered a North-German army, supported by the Dukes of Brabant and Holland, and the Counts of Boulogne and Flanders. John sent a mercenary force under the Earl of Salisbury to join him, and the combined host entered France and met King Philip at Bouvines, near Lille. John had trusted that his own attack on southern France would have distracted the French king's attention, but Philip left him almost unopposed, and gathered the whole force of France to oppose the Germans and Flemings. While John was overrunning Poitou and storming Angers, Philip was crushing his confederates. At the battle of Bouvines the combined army was scattered to the winds; the emperor was put to flight, and the Earl of Salisbury and the Count of Boulogne captured (July 27, 1214). Otho of Saxony was ruined by the fight, and never raised his head again; nor did any German host invade France for the next three hundred years. John, though he had not been present at the fight, was as effectually crushed as Otho. Free from danger from the north, the French king turned upon him, and drove him out of his ephemeral conquests in Poitou, so that he had to return to England completely foiled and beaten. [Sidenote: =The barons take up arms.=]