It was owing to the war in Spain that the English hold over the south of France was first shaken; for the Black Prince, who had been created Duke of Guienne, unwisely listened to the exiled King of Castile, Pedro the Cruel, who came to Bordeaux begging his assistance against the usurper of his throne. This was his illegitimate brother, Henry of Trastamara. The English Prince at once declared that chivalry demanded that he should help the rightful king. Perhaps he remembered the strong bond that there had been between England and Castile ever since his great-grandfather, Edward I, had married the Spanish Eleanor: perhaps it was the promise of large sums of money that Pedro declared would reward the victorious troops: it is more likely, however, that the fiery soldier was moved by the news that Henry of Trastamara had gained his throne through French assistance and by the deeds of arms of the renowned Du Guesclin. [Sidenote: Battle of Navarette] In 1367 the English Prince crossed the Pyrenees, and at Navarette, near the river Ebro, his English archers and good generalship proved a match once more for his foes. Although the Spaniards were in vastly superior numbers they were mown down as they rashly charged to the attack; and Henry of Trastamara was driven from the field, leaving Du Guesclin a prisoner and his brother Pedro once more able to assert his kingship. The real victors of Navarette now had cause to repent their alliance. Sickness, due to the heat of the climate and strange food, had thinned their ranks even more than the actual warfare: the money promised by Pedro the Cruel was not forthcoming; indeed, that wily scoundrel, after atrocities committed against his helpless prisoners that fully bore out his nickname, had slipped away to secure his throne, while the Black Prince was in no position to pursue him, and could gain little satisfaction by correspondence. Sullen and weary, with the fever already lowering his vitality that was finally to cut short his life, Edward of Wales arrived in Bordeaux with his almost starving ‘companies’. Because he had no money to pay them, he set them free to ravage southern France, while in order to fill his exchequer he imposed a tax on every hearth in Guienne. These measures proved him no statesman, whatever his generalship. In the early days of the Hundred Years’ War Guienne had looked coldly on Paris, and appreciated a distant ruler who secured her liberty of action; now, victim of a policy of mingled pillage and exactions, she soon came to regard her English rulers as foreign tyrants. Thus an appeal was made by the men of Guienne to Charles V, and he, in defiance of the terms of the Treaty of Bretigni, summoned Prince Edward to Paris--as though he were his vassal--to answer the charges made against him. ‘Gladly we will answer our summons,’ replied the Prince, when he heard. ‘We will go as the King of France has ordered us, but with helm on head and sixty thousand men.’