King Philip VI died and was succeeded by his son, who became King John II. Another rival claimant to the French throne, John’s cousin Charles “the Bad,” King of Navarre, plotted against him. However, Charles the Bad was put in prison, though his allies and family in Normandy continued resisting John II. The French attacked Evreux and Breteuil, both part of Charles the Bad’s territories. They conquered Evreux and began to besiege Breteuil. Charles the Bad’s men defended Breteuil using “Greek fire,” a chemical used in warfare that burns easily and is difficult to extinguish. Kept at bay, the French tried filling the castle’s moat.

Edward III’s son, now known as the “Black Prince,” sailed for Aquitaine to deal with pro-French sympathizers. After successfully subjugating the area, the Black Prince set out for Normandy to aid the supporters of Charles the Bad. Eager to stop the Black Prince’s army from looting the countryside, John II agreed to spare the men at Breteuil as long as they surrendered the castle and their possessions. A detachment of English defeated a French battalion, forcing them to take refuge in the castle of Romorantin. Despite the Black Prince’s larger force, the French were able to resist him and inflict casualties on his army.