A heraldic opinion by Sir John Vanbrugh (Clarencieux King of Arms) on the rightful arms of the Isle of Man upon James, Duke of Atholl's accession to sovereignty in 1735. The document traces the heraldic history of Man from 1475, examining seals, patents, and the arms borne by various lords and kings, including discussion of the ship seal, the three-legged emblem, and the Stanley family's quarterings.