In the towns, where the system of forced labour was applied with even more rigour than in the country, strikes and combinations became frequent among the lower craftsmen. In the country the free labourers found allies in the villeins whose freedom from manorial service was questioned. These were often men of position and substance, and throughout the eastern counties the gatherings of "fugitive serfs" were supported by an organized resistance and by large contributions of money on the part of the wealthier tenantry. [Sidenote: Renewal of the War] With plague, famine, and social strife in the land, it was no time for reaping the fruits even of such a victory as Crecy. Luckily for England the pestilence had fallen as heavily on her foe as on herself. A common suffering and exhaustion forced both countries to a truce, and though desultory fighting went on along the Breton and Aquitanian borders, the peace which was thus secured lasted with brief intervals of fighting for seven years. It was not till 1355 that the failure of a last effort to turn the truce into a final peace again drove Edward into war. The campaign opened with a brilliant prospect of success. Charles the Bad, King of Navarre, held as a prince of descent from the house of Valois large fiefs in Normandy; and a quarrel springing suddenly up between him and John, who had now succeeded his father Philip on the throne of France, Charles offered to put his fortresses into Edward's hands. Master of Cherbourg, Avranches, Pontaudemer, Evreux and Meulan, Mantes, Mortain, Pontoise, Charles held in his hands the keys of France; and Edward grasped at the opportunity of delivering a crushing blow. Three armies were prepared to act in Normandy, Britanny, and Guienne. But the first two, with Edward and Henry of Derby, who had been raised to the dukedom of Lancaster, at their head, were detained by contrary winds, and Charles, despairing of their arrival, made peace with John. Edward made his way to Calais to meet the tidings of this desertion and to be called back to England by news of a recapture of Berwick by the Scots. But his hopes of Norman co-operation were revived in 1356. The treachery of John, his seizure of the King of Navarre, and his execution of the Count of Harcourt who was looked upon as the adviser of Charles in his policy of intrigue, stirred a general rising throughout Normandy. Edward at once despatched troops under the Duke of Lancaster to its support. But the insurgents were soon forced to fall back. Conscious of the danger to which an English occupation of Normandy would expose him, John hastened with a large army to the west, drove Lancaster to Cherbourg, took Evreux, and besieged Breteuil. [Sidenote: The Black Prince]