Thomas succeeded as Baron on his father's death while still a child, and his affairs were administered by his grandfather, Sir Andrew Gray of Fowlis, until he came of age.
[1] In 1437, following the regicide of James I of Scotland, Thomas Maule laid claim to the barony of Brechin-Barclay.
Walter Stewart, Earl of Atholl, who was executed for his role in the assassination, had possessed the lands after the death of Margaret Barclay, his wife and the heiress to the barony.
The succession of the barony of Brechin-Barclay had not been formally carried out, and Atholl's heir, David Stewart had died prior to the murder of the king.
Thomas Maule, her great-grandson, had the greatest claim, but was only able to take possession of part of it, most being annexed by the crown.