- (c. 1310-1361) First Duke of Lancaster.
- Only son of Henry, 3rd Earl of Lancaster, and Maud Chaworth, heiress to vast estates.
- He was of royal descent, as a great-grandson of Henry III of England, and a grand-nephew of Edward I. Blanche d'Artois, his paternal grandmother, was a granddaughter of Louis VIII of France.
- Married Isabella de Beaumont. She was the daughter of Henry, 1st Baron Beaumont, a veteran of the Anglo-Scottish wars where he is reputed to have developed the battle strategy that led to the victories of Crécy and Agincourt.
- Served in France during the hostilities of the first phase of the Hundred Years' War, especially during the Rheims campaign of 1359-1360. Was one of the main negotiators of the Treaty of Brétigny, which obtained favourable terms for England.
- Had two daughters by Isabella of Beaumont, Maud (b. 1339) and Blanche (b. 1345). Maud died without descendance, and her sister Blanche became sole heir of their father's vast estates. These passed on to John of Gaunt, who became Duke of Lancaster when he married Blanche. Ultimately, the Lancaster estates were merged into the crown's as the Duchy of Lancaster, when Henry of Bolingbroke, the son of Blanche and John of Gaunt, deposed his cousin Richard II, and was crowned as Henry IV.
- Henry Grosmont died of the plague in 1361.
Emrique Duque dAllamcastro
Chronicle entries in which Henry of Grosmont appears:
Crónica de D. João I, part 2, ch. 88