attacking the forces of John and the Earl of Arundel, seizing their baggage train. By now both sides were tiring, and they agreed to the temporary Truce of Tillières. The war resumed in 1195 when Philip once again besieged Verneuil. He continued the siege in secret as Richard arrived to negotiate in person; when Richard found out, he swore revenge and left. Philip now pressed his advantage in northeastern Normandy, where he conducted a raid at Dieppe, burning the English ships in the harbor while repulsing an attack by Richard at the same time. Philip now marched southward into the Berry region. His primary objective was the fortress of Issoudun, which had just been captured by Richard's mercenary commander, Mercadier. The French king took the town and was besieging the castle when Richard stormed through French lines and made his way in to reinforce the garrison, while at the same time, another army was approaching Philip's supply lines. Philip called off his attack, and another truce was agreed. The war slowly turned against Philip over the course of the next three years. Political and military conditions seemed promising at the start of 1196 when Richard's nephew Arthur I, Duke of Brittany ended up in Philip's hands, and he won the Siege of Aumale, but Philip's good fortune did not last. Richard won over a key ally, Baldwin of Flanders, in 1197. The same year, the Holy Roman Emperor Henry VI died and was succeeded by Otto IV, Richard's nephew, who put additional pressure on Philip. Finally, many Norman lords were switching sides and returning to Richard's camp. This was the state of affairs when Philip launched his campaign of 1198 with an attack on Vexin that was pushed back and then compounded by the Flemish invasion of Artois. On 27 September, Richard entered Vexin, taking Courcelles-sur-Seine and Boury-en-Vexin before returning to Dangu. Philip, believing that Courcelles was still holding out, went to its relief. Discovering what was happening, Richard decided to attack the French king's forces, catching Philip by surprise. Philip's forces fled and attempted to reach the fortress of Gisors. Bunched together, the French knights with king Philip attempted to cross the Epte River on a bridge that promptly collapsed under their weight, almost drowning Philip in the process. He was dragged out of the river and shut himself up in Gisors. Philip soon planned a new offensive, launching