Thomas de Mowbray, 1st Duke of Norfolk

His Grace The Duke of Norfolk
Thomas de Mowbray, 1st Earl of Nottingham, from a drawing of his seal, 1389
Born	22 March 1366 Epworth, Lincolnshire, England.
Died	22 September 1399 (aged 33) Venice, Republic of Venice, Italy.
Buried	Venice, Italy.
Spouse(s)	Elizabeth le Strange Lady Elizabeth FitzAlan
Issue	Thomas de Mowbray, 4th Earl of Norfolk John de Mowbray, 2nd Duke of Norfolk Elizabeth de Mowbray, Countess of Suffolk Isabel de Mowbray, Baroness Berkeley Margaret de Mowbray, Lady Howard
Father	John de Mowbray, 4th Baron Mowbray
Mother	Elizabeth de Segrave

Thomas de Mowbray, 1st Duke of Norfolk, KG (22 March 1366 – 22 September 1399) was an English peer. His family were ancient, and by the time Thomas reached adulthood, they were extremely influential in national politics. He himself claimed a direct bloodline from King Edward I. His father died when Thomas and his elder brother were young. However, John soon died, and Thomas inherited the Earldom of Nottingham. He had probably been friends with the king, Richard II, since he was young, and as a result, he was a royal favourite, a role he greatly profited from. He accompanied Richard on his travels around the kingdom and was elected to the Order of the Garter. Richard's lavish dispersal of his patronage made him unpopular with parliament and other members of the English nobility, and Mowbray fell out badly with the king's uncle, John of Gaunt.

Mowbray journeyed into Scotland with the king when he invaded in 1385, although it is possible that their friendship was waning at this point. Richard had a new favourite—Robert de Vere—and Mowbray became increasingly close to Richard Fitzalan, Earl of Arundel, whose daughter Elizabeth Mowbray married. The king already distrusted Arundel, and Mowbray's new circle included the equally estranged Thomas of Woodstock, Duke of Gloucester. Together they plotted against the king's chancellor, the Duke of Suffolk, appealling him in parliament. Suffolk was impeached, and a council was appointed to oversee the king. Mowbray gradually became disillusioned with his comrades, perhaps because of the brutal revenges they took, and by 1389, he was back in the king's favour. Mowbray entered into jousts, led embassies and joined Richard on his 1395 invasion of Ireland, negotiating successfully with the Irish Kings. By now, the king felt sufficiently restored to power to attack his enemies, which seems to have culminated in Mowbray's killing of Gloucester in Calais in 1397 on Richard's orders. Probably in a quid pro quo, Mowbray was made Duke of Norfolk soon after.

In the meantime, Mowbray had fallen out with John of Gaunt's eldest son, Henry Bolingbroke, and they arranged a trial by combat. No sooner had this begun than the king cancelled it in person. He exiled them both: Mowbray for life, Bolingbroke for ten years. Mowbray took a vow of pilgrimage, intending to travel to Jerusalem. He reached Venice, but in September 1399, he died before leaving it. By his wife Elizabeth, he left two sons and three daughters. The eldest son, Thomas, inherited his father's earldom of Norfolk, but rebelled against the king in 1405 and was beheaded for treason. Mowbray's second son, also John, inherited the dukedom and served the crown faithfully.