Olaf the Black
a mid 13th century sea-king who ruled the Isle of Man and parts of the Hebrides.
Óláfr was the son of Guðrøðr Óláfsson, King of the Isles, King of Dublin, and his wife Finnguala, granddaughter of Muirchertach Mac Lochlainn, High King of Ireland, King of Cenél nEógain. Óláfr was a younger son of his father; his elder brother Rögnvaldr more than likely had a different mother. According to the Chronicle of Mann, Guðrøðr appointed Óláfr as heir since he had been born "in lawful wedlock". Whether or not this is the case, on Guðrøðr's death in 1187 the Manxmen instead appointed Rögnvaldr as king, as he was a capable adult and Óláfr was a mere child. Rögnvaldr ruled the Crovan dynasty's island-kingdom for almost 40 years, during which time the half-brothers vied for the kingship