Edward's forces met little resistance, sacking numerous settlements, until they reached the Loire river at Tours. They were unable to take the castle or burn the town due to a heavy rainstorm. This delay allowed King John to attempt to pin down and destroy Edward's army. John, who had been besieging Breteuil in Normandy, organised the bulk of his army at Chartres to the north of Tours. In order to increase the speed of his army's march, he dismissed between 15,000 and 20,000 of his lower quality infantry, just as Edward turned back to Bordeaux. The French rode hard and cut in front of the English army, crossing the bridge over the Vienne at Chauvigny. Learning of this, the Black Prince quickly moved his army south. Historians disagree over whether the outnumbered English commander was seeking battle or trying to avoid it. In any case, after preliminary manoeuvres and failed negotiations for a truce, the two armies faced off, both ready for battle, near Poitiers on Monday, 19 September 1356.