The "Bannatyne manuscript" states that the flag was unfurled at the Battle of Bloody Bay in 1480. The manuscript related that during the battle, the clan's chief, William Dubh (c. 1415–1480), was slain, and in consequence his clan began to lose heart. A priest then ordered the flag's bearer, Murcha Breac, to unfurl the Fairy Flag to rally the clan. Up until this point, the MacLeods of Harris and Dunvegan were on the opposing side of their kinsmen, the MacLeods of Lewis. However, once the MacLeods of Lewis noticed that the flag had been unfurled, they switched sides to join forces with their kinsmen. Unfortunately for both MacLeod clans, the outcome of the battle had already been determined and they were on the losing side. Among the vast numbers of MacLeods slain were Murcha Breac and the twelve guardians of the flag. William Dubh is buried on the island of Iona with his predecessors, and the body of Murcha Breac is placed within the same tomb. The manuscript states that this was the greatest honour which could be bestowed upon his remains. R. C. MacLeod suggested that the MacLeod effigy within Iona Abbey may mark the burial of the first chiefs of the clan, as well as William Dubh, and the mentioned standard bearer. William Dubh is thought to have been the last MacLeod chief buried on Iona; his son, Alasdair Crotach (1450–1547), was buried in St Clements Church, on Harris.