House of Valois the senior descendant of Philip IV of France. Charles' character eventually alienated both the French and English monarchs, because he readily switched sides whenever it suited his interest. In 1356, Edward, the Black Prince, eldest son and heir of Edward III, led an army to a chevauchée in France. John pursued the Black Prince, who tried to avoid battling the French king's superior force. Negotiations broke down. In the Battle of Poitiers, the French suffered another humiliating defeat, and their king was captured. Edward hoped to capitalize on the victory by invading France and having himself crowned at Reims. But
Edward the Black Prince already warned his father of the intentions of the French king, but there was evidently a party at Edward's court that was jealous of his power, and his warnings were slighted. In April 1369, however, war was declared. Edward sent the Earls of Cambridge and Pembroke to his assistance, and Sir Robert Knolles, who now again took service with, him, added much to his strength. The war in Aquitaine was desultory, and, though the English maintained their ground fairly in the field, every day that it was prolonged weakened their hold on the country. On 1 January 1370 the Black