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 the face of threats of secession by the Gascon nobles. He was one of England's principal negotiators in the diplomatic exchanges with France that led to the Truce of Leulingham in 1396, and he initially agreed to join the French-led Crusade that ended in the disastrous Battle of Nicopolis, but withdrew due to ill-health and the political problems in Gascony and England. For the remainder of his life, John of Gaunt occupied the role of valued counsellor of the king and loyal supporter of the Crown. He did not even protest, it seems, when his younger brother Thomas was murdered