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
The Twelve of England sealed by the marriage of John I of Portugal and Philippa of Lancaster, daughter of John of Gaunt) and before the death of John the Gaunt in 1399. Narrowing the window further, it was probably sometime after 1389, when John of Gaunt returned to England from his failed Iberian campaign, and before the death of John of Gaunt's wife, the Duchess of Lancaster, Constance of Castile in 1394. The common date frequently cited is 1390. The Duchess's Castilian nationality may lend credence to such an event, and her twelve ladies-in-waiting were also, likely, Castilian rather than English, which may explain