High Quality Content by WIKIPEDIA articles! Constantine, son of Cuilén (Mediaeval Gaelic: Causantín mac Cuiléin, Modern Gaelic: Còiseam mac Chailein), known in most modern regnal lists as Constantine III, (before 971-997) was king of Scots from 995 to 997. He was the son of Cuilén, King of Scotland (Cuilén mac Iduilb).