After winning his spurs at the Battle of Crécy, the Black Prince emerged as the finest commander of the Hundred Years' War. In 1356, the outbreak of civil war in France encouraged King Edward III to mount another invasion. On September 9, at Poitiers, the Black Prince defeated the French and captured King John II of France. The French agreed to a peace treaty at Brétigny in 1360. The first phase of the Hundred Years' War ended in complete triumph for England.