Meanwhile Henry of Trastámara made war upon Aquitaine, took Bagnères and wasted the country. Fearing that Charles of Navarre would not allow him to return through his dominions, the prince negotiated with the King Peter IV of Aragon for a passage for his troops. Peter IV made a treaty with him, and when Charles of Navarre heard of it he agreed to allow the prince, the Duke of Lancaster, and some of their lords to pass through his country; so they returned through Roncesvalles, and reached Bordeaux early in September 1367.