Sir Thomas Stewart, Master of Mar was an illegitimate son of Alexander Stewart, the earl of Mar.
He was the great-grandson of King Robert II of Scotland.
He died before August 1432.
[1] Thomas married Elizabeth, the widow of John Stewart, 2nd Earl of Buchan, who was daughter of Archibald Douglas, 4th Earl of Douglas and Margaret Stewart, Lady of Galloway.
[2] They were required to obtain a marriage license, which was granted on 1 May 1427, due to their degrees of consanguinity and affinity.