Battle of Bloody Bay The Battle of Bloody Bay , or Blàr Bàgh na Fala in Scottish Gaelic , was a naval battle fought near Tobermory , Scotland . It was fought on the coast of Mull two miles north of Tobermory , between John of Islay , Earl of Ross , the Lord of the Isles and chief of Clan Donald ; and his son , Angus Og Macdonald . The precise date of the battle varies in sources , from 1480 to 1483 . After the battle , in which Angus Og Macdonald emerged victorious , the latter seized power from his father , and held it for a decade . However , Angus ' s victory would prove pyrrhic . Many clansmen had died in the battle and nearly half the clan ' s fleet had been sunk , as a result of which the power of the Lords of the Isles was henceforth greatly diminished . Angus , last of the independent Lords of the Isles , would himself be murdered ten years later , in 1490 . Background . In 1476 , James III of Scotland was informed of a secret treaty made by John of Islay with Edward IV of England . James stripped John of his earldom , as well as the sheriffdoms of Nairn and Inverness , and the lordships of Kintyre and Knapdale , but confirmed him with the remainder of his lands and the title Lord of the Isles . The designation of Lord of the Isles , however , was from this point forward to be granted by the crown , rather than self - assumed . And John had lost much more than land and titles ; he had lost prestige and standing among his own kin . The Lordship had always depended on territorial expansion to give life to its warrior values ; but now that it was contracting , all of the latent tensions came forth , finding expression in the person of Angus Óg . Angus , according to Hugh Macdonald , ejected John both from the leadership of the clan and from his own home , forcing him to seek shelter under an old boat . John gathered his remaining supporters in an attempt to quash his son ' s rebellion . John ' s fleet of galleys met those of Angus sometime in the early 1480s - we cannot be more precise than that - off the coast of Mull to the north - west of the present town of Tobermory , an area ever afterwards to be known as Bloody Bay . The Battle . John of Islay , Earl of Ross , was supported by men from the Clan MacLean , Clan MacLeod , and Clan MacNeil . He was opposed by his son , Angus Og Macdonald , who was supported by Allan Macruari , chief of the Clan MacDonald of Clanranald , Donald Gallach , chief of the Clan MacDonald of Sleat , and Domhnall Mac Aonghais ( " Donald Mac Angus " ) , chief of the Clan MacDonald of Keppoch as well as the MacLeods of Lewis . In bitter fighting , Aonghas defeated the galleys of his father ' s west highland allies . The " Bannatyne manuscript " states that William Dubh , chief of the MacLeods , was killed early on , and at the fall of their chief , the MacLeods began to give way . However , a priest named Callum Clerich made the keeper of the Fairy Flag unfurl his banner . The manuscript states that when the MacLeod ' s kinsmen , the MacLeods of Lewis , switched sides upon seeing the sacred flag unfurled and joined the forces supporting John . However , the fate of the battle was already decided and the forces of Angus won the day . A large number of the clan was killed during the conflict , including the bearer of the flag , Murcha Beach , as well as the twelve men who were tasked with the flag ' s protection . Hector Odhar Maclean , the chief of Clan MacLean and John of Islay ' s naval commander , was taken prisoner . William Dubh MacLeod , chief of Clan MacLeod , was killed along with many of his clan . Aftermath . After the battle , Angus Og Macdonald took over power from his father , and held it for a decade until he was murdered . However , many clansmen died , and nearly half the clan ' s fleet had been sunk . Angus himself would be murdered ten years later . As a result of Bloody Bay and other reverses , the power of the Lords of the Isles would henceforth be greatly diminished .