He died at Dumbarton Castle.
Thomas Stewart, 2nd Earl of Angus, was born 1329/31 the son of John Stewart, 1st Earl of Angus and Margaret Abernethy. He married Margaret de St Clair (Sinclair), daughter of Sir Henry Sinclair of Roslin and Alice de Fenton, (Papal dispensation 3 Jun 1353). He died in 1361 at Dunbarton Castle, from the plague while imprisoned for alleged complicity in the murder of King David II's mistress, Catherine Mortimer. Margaret married secondly Sir John Sinclair of Herdmanstoun. He succeeded to the title of 2nd Earl of Angus [S., 1329] on 9 December 1331. He fought in the taking of Berwick in May 1355, where he commanded. He was one of the eight lords, of whom three were to place themselves in the hands of the English as security for the release of King David II. He held the office of Great Chamberlain [Scotland] from 1357 to 1358. On 18 August 1359 he had a safe conduct for four ships of Flanders, but he broke his engagement. In March 1359/60 he was charged to return to England to fulfill his obligations as hostage.