Matilda was the daughter of Robert I (d.1329) and his second wife Elizabeth de Burgh, daughter of Richard de Burgh, earl of Ulster. Very little is known of Matilda’s career. She was married, in what looks like a rather disparaging match, to a squire named Thomas Isaac. She and Thomas had two daughters. Joanna, married to John MacDougall, lord of Lorn, and Katherine, who died unmarried at Stirling. Matilda died at Aberdeen on 20 July 1353 and was buried alongside her father and other members of the Bruce ‘royal’ family in Dunfermline abbey.