One immediate consequence of the "Black Death" was the renewal of the truce between England and France by repeated agreements which lasted from 1347 to 1355. During this interval Philip of France died, in 1350, and was succeeded by his son John. The war did not entirely cease, but became local and spasmodic. In Brittany the factions which supported the two claimants to the ducal title were so embittered that they never laid down their arms. In 1351 the French noblesse of Picardy, apparently without their master's knowledge or consent, made an attempt to surprise Calais, which was beaten off with some difficulty by King Edward in person. There was also constant bickering on the borders of Guienne. But the main forces on both sides were not brought into action till the series of truces ran out in 1355. From that time onward the English took the offensive with great vigour. Edward, prince of Wales, ravaged Languedoc as far as the Mediterranean, while his younger brother John of Gaunt, duke of Lancaster, executed a less ambitious raid in Picardy and Artois. In the south this campaign marked real progress, not mere objectless plunder, for it was followed by the reconquest of great districts in Périgord and the Agenais, which had been lost to England since the 13th century. A similar double invasion of France led to even greater results in the following year, 1356. While Lancaster landed in Normandy, and with the aid of local rebels occupied the greater part of the peninsula of the Côtentin, the prince of Wales accomplished greater things on the borders of Aquitaine. After executing a great circular sweep through Périgord, Limousin and Berry, he was returning to Bordeaux laden with plunder, when he was intercepted by the king of France near Poitiers. The battle that followed was the most astonishing of all the English victories during the Hundred Years' War. The odds against the prince were far heavier than those of Creçy, but by taking up a strong position and using the national tactics which combined the use of archery and dismounted men-at-arms, the younger Edward not merely beat off his assailants in a long defensive fight, but finally charged out upon them, scattered them, and took King John prisoner (Sept. 19, 1356). The English ravage France. Peace of Brétigny.