In 1270 he was one of the four citizens to whose keeping the muniments of the city were entrusted.
By an undated charter still preserved with the corporation's muniments he surrendered to the burgesses all the liberties given them by his predecessors (antecessores) when they founded the town.
He steadily investigated the muniments of all the colleges, and in 1667 made his first journey to London, where he visited Dugdale, who introduced him into the Cottonian library, and Prynne showed him the same civility for the Tower records.
The muniments of the abbacy, preserved in the archives of the earl of Morton, were edited by Cosmo Innes for the Bannatyne Club and published in 1837 under the title of Liber sancte Marie de Melros.
Froissart errs in describing this knight as Thomas, lord of Berkeley, for the covenant made in 1360 for the release of Maurice is still among the Berkeley muniments, the ransom being stated at 1080.