John of Gaunt of Castile. As his father and elder brother, Edward, the Black Prince, became incapacitated due to poor health, Gaunt assumed control of many government functions, and rose to become one of the most powerful political figures in England. He was faced with military difficulties abroad and political divisions at home, and disagreements as to how to deal with these crises led to tensions between Gaunt, the English Parliament, and the ruling class, making him an extremely unpopular figure for a time. John exercised great influence over the English throne during the minority of King Richard II, and the ensuing periods
John of Gaunt in Jure uxoris by right of his second wife, Constance of Castile, whom he had married in 1371. However, crisis ensued almost immediately in his absence, and in 1387 King Richard's misrule brought England to the brink of civil war. Only John, on his return to England in 1389, succeeded in persuading the Lords Appellant and King Richard to compromise to usher in a period of relative stability. During the 1390s, John's reputation of devotion to the well-being of the kingdom was largely restored. During his second marriage, John of Gaunt had entered into an extra-marital love affair with Katherine