 His surname is given variously as "de Lorne" (of Lorne) or as "de Ergadia" (of Argyll), the surnames used by the higher-ranking members of the MacDúghaill kindred and the old lords of Argyll; he was certainly a kinsman of John Gallda, the MacDúghaill Lord of Argyll who died sometime between 1371 and 1388.He was misidentified in Wood's "Peerage" (and those using that work thereafter) as a son of Sir John Drummond of Stobhall, the ballie of the "abthen" of Dull; this would have made him a brother of Anabella Drummond, wife and queen to King Robert III of Scotland.He is styled "Petri" in a few sources, meaning perhaps that his father's name was Peadar (or Peter), though this is far from certain as that name was unusual at the time anywhere in Scotland.