Thomas de Mowbray, 1st Duke of Norfolk

Thomas de Mowbray, 1st Duke of Norfolk
Arms of Thomas de Mowbray, 1st Duke of Norfolk
Spouse(s)	Elizabeth le Strange Elizabeth Arundel
Issue Thomas de Mowbray, 4th Earl of Norfolk John de Mowbray, 2nd Duke of Norfolk Elizabeth Mowbray Isabel Mowbray Margaret Mowbray
Father	John de Mowbray, 4th Baron Mowbray
Mother	Elizabeth de Segrave
Born	22 March 1367 or 1368
Died	22 September 1399 (aged 31 or 32) Venice, Republic of Venice
Buried	Venice, Italy

Thomas de Mowbray, 1st Duke of Norfolk, KG, Earl Marshal (22 March 1367 or 1368 – 22 September 1399) was an English peer. As a result of his involvement in the power struggles which led up to the fall of Richard II, he was banished and died in exile in Venice.

Mowbray was the second son of John de Mowbray, 4th Baron Mowbray, and Elizabeth de Segrave, suo jure Lady Segrave, daughter and heiress of John de Segrave, 4th Baron Segrave, by Margaret, daughter and heiress of Thomas of Brotherton, son of Edward I. He had an elder brother, John de Mowbray, 1st Earl of Nottingham, and three sisters, Eleanor, Margaret and Joan (for details concerning his siblings see the article on his father, John de Mowbray, 4th Baron Mowbray).

In April 1372, custody of both Thomas and his elder brother, John, was granted to Blanche Wake, a sister of their grandmother, Joan of Lancaster.

On 10 February 1383, he succeeded his elder brother, John Mowbray, 1st Earl of Nottingham, as Baron Mowbray and Segrave, and was created Earl of Nottingham on 12 February 1383. On 30 June 1385 he was created Earl Marshal for life, and on 12 January 1386 he was granted the office in tail male. He fought against the Scots and then against the French. He was appointed Warden of the East March towards Scotland in 1389, a position he held until his death.