King of Scotland from 1390 to 1406, son of Robert II.; was a quite incompetent ruler, and during his reign the barons acquired an ascendency and displayed a disloyalty which greatly diminished the power of the Crown both in his and succeeding reigns; the government fell largely into the hands of the king's brother, the turbulent and ambitious Robert, Duke of Albany; an invasion by Henry IV. of England and a retaliatory expedition under Archibald Douglas, which ended in the crushing defeat of Homildon Hill, are the chief events of the reign (1340-1406).