Question: Who is Hugh Of Sleat's paternal grandfather?
Sentence (from "Alexander of Islay, Earl of Ross"): Alexander of Islay or Alexander MacDonald (died 1449) was a medieval Scottish nobleman, who succeeded his father Domhnall of Islay as Lord of the Isles (1423–1449) and rose to the rank of Earl of Ross (1437–49).
Relevant evidence: Yes