John of Gaunt was an English soldier and statesman as well as a brother of Edward, the Black Prince. In 1359, John married Blanche, daughter of Henry, Duke of Lancaster. When Henry died, John became the next Duke.

John played an important part in the wars of the period between England and France and between England and spain. He commanded a division of the English army, led by the Black Prince, that defeated the army of Henry (later Henry II, King of Castile and Leon) at Najera in 1367.

As a result of his econd marriage to Constance, daughter of Peter the Cruel (King of Castile and Leon), John laid claim to the throne of Castile. During the Hundred Years’ War, he aided the Black Prince against France and established English rule over most of southern France. After a severe illness forced the return of the Black Prince to England, John took command of the English armies. But by 1380, he had lost much of the territory the English had previously won.

In 1386, John invaded Castile, but was defeated by King John I of Castile and Leon. The following year, John of Gaunt gave up his claim to Castile and Leon upon the marriage of his daughter to Henry III who would himself become King of those countries.

John of Gaunt was also prominent in English affairs. Together with Alice Perrers, his father’s mistress, John dominated the English government. He was opposed by Parliament and by the Black Prince. In 1376, Parliament banished Alice Perrers and curtailed John’s powers. The death of the Black Prince that year and the dissolution of Parliament, however, enabled John to regain his power. In 1377, upon the death of King Edward III and the ascension of Richard II (John’s nephew and son of the Black Prince), John gave up his control of the government and thereafter played the role of peacemaker. He also supported King Richard, who named John the Duke of Aquitaine in 1390.

In 1396, after the death of his second wife, John married his mistress, Catherine Swynford, and King Richard legitimized their children the following year. Saddened by the exile of his son, Henry of Lancaster in 1398, John died on February 3 of the following year.

John of Gaunt, b. Ghent 1340; d. Leicester Castle, Feb. 1399; Duke of Lancaster; m. (1) 19 May 1359, Blanche, d. 31 Sep. 1369, dau. of Henry, Duke of Lancaster; son of Henry, Earl of Lancaster (17-29); m. (2) Jun. 1371, Constance, d. Jun. 1394, eldest dau. and coh. Pedro I “The Cruel”, King of Castile and Leon; m. (3) Jan. 1396/7, Catherine (Roet) Swynford, b. 1350; d. 10 May 1403; dau. of Sir Paon Roet, a Gascon, and widow of Sir Hugh Swynford. (G. E. Cokayne’s (new revised) “Complete Peerage,” vols. I-XII pt. 2, 1910-1959 - V, 320, 736 chart, VII 415; S. Armitage Smith, “John of Gaunt,” reprint 1964).55