June 1475 that the menace of new leagues against his dominions on the upper Rhineland forced him to withdraw. So broken was his army that he could not, even if he would, have aided in carrying out the schemes of the preceding year. But an English invasion would secure him from attack by Lewis till his forces could be reorganized; and with the same unscrupulous selfishness as of old Charles pledged himself to co-operate and called on Edward to cross the Channel. In July Edward landed with an army of twenty-four thousand men at Calais. In numbers and in completeness of equipment no such force had as yet left English shores. But no Burgundian force was seen on the Somme; and after long delays Charles proposed that Edward should advance alone upon Paris on his assurance that the fortresses of the Somme would open their gates. The English army crossed the Somme and approached St. Quentin, but it was repulsed from the walls by a discharge of artillery. It was now the middle of August, and heavy rains prevented further advance; while only excuses for delay came from Britanny and it became every day clearer that the Burgundian Duke had no real purpose to aid. Lewis seized the moment of despair to propose peace on terms which a conqueror might have accepted, the security of Britanny, the payment of what the English deemed a tribute of fifty thousand crowns a year, and the betrothal of Edward's daughter to the Dauphin. A separate treaty provided for mutual aid in case of revolt among the subjects of either king; and for mutual shelter should either be driven from his realm. In spite of remonstrances from the Duke of Burgundy this truce was signed at the close of August and the English soldiers recrossed the sea. [Sidenote: Edward's policy]