The negotiation of this alliance occupied the whole of 1337; it ended in a promise of the Emperor on payment of 3000 gold florins to furnish two thousand men-at-arms. In the opening of 1338 an attack of Philip on the Agenois forced Edward into open war. His profuse expenditure however brought little fruit. Though Edward crossed to Antwerp in the summer, the year was spent in negotiations with the princes of the Lower Rhine and in an interview with the Emperor at Coblentz, where Lewis appointed him Vicar-General of the Emperor for all territories on the left bank of the Rhine. The occupation of Cambray, an Imperial fief, by the French king gave a formal ground for calling the princes of this district to Edward's standard. But already the great alliance showed signs of yielding. Edward, uneasy at his connexion with an Emperor under the ban of the Church and harassed by vehement remonstrances from the Pope, entered again into negotiations with France in the winter of 1338; and Lewis, alarmed in his turn, listened to fresh overtures from Benedict, who held out vague hopes of reconciliation while he threatened a renewed excommunication if Lewis persisted in invading France. The non-arrival of the English subsidy decided the Emperor to take no personal part in the war, and the attitude of Lewis told on the temper of Edward's German allies. Though all joined him in the summer of 1339 on his formal summons of them as Vicar-General of the Empire, and his army when it appeared before Cambray numbered forty thousand men, their ardour cooled as the town held out. Philip approached it from the south, and on Edward's announcing his resolve to cross the river and attack him he was at once deserted by the two border princes who had most to lose from a contest with France, the Counts of Hainault and Namur. But the king was still full of hope. He pushed forward to the country round St. Quentin between the head waters of the Somme and the Oise with the purpose of forcing a decisive engagement. But he found Philip strongly encamped, and declaring their supplies exhausted his allies at once called for a retreat. It was in vain that Edward moved slowly for a week along the French border. Philip's position was too strongly guarded by marshes and entrenchments to be attacked, and at last the allies would stay no longer. At the news that the French king had withdrawn to the south the whole army in turn fell back upon Brussels. [Sidenote: England and the Papacy]