John of Gaunt return for a large annual payment and the marriage of their daughter Catherine to John of Trastámara's son Henry. John left Portugal for Aquitaine, and he remained in that province until he returned to England in November 1389. This effectively kept him off the scene while England endured the major political crisis of the conflict between Richard II and the Lords Appellant, who were led by John of Gaunt's younger brother Thomas of Woodstock, Duke of Gloucester. Only four months after his return to England, in March 1390, Richard II formally invested Gaunt with the Duchy of Aquitaine, thus providing
John of Gaunt was simply abandoned and the army returned ingloriously to England. John of Gaunt received most of the blame for the debâcle. Partly as a result of these failures, and those of other English commanders at this period, John was one of the first important figures in England to conclude that the war with France was unwinnable because of France's greater resources of wealth and manpower. He began to advocate peace negotiations; indeed, as early as 1373, during his great raid through France, he made contact with , brother and political adviser of Pope Gregory XI, to let the pope know