Aonghus Mór mac Domhnaill was a leading figure in the thirteenth-century kingdoms of the Isles and Scotland. He was a son of Domhnall mac Raghnaill, the eponym of Clann Domhnaill, a branch of Clann Somhairle. Aonghus Mór appears to have succeeded his father in the mid part of the thirteenth century. At the time, the rulers of the Isles were fiercely independent of the Scottish Crown, and owed nominal allegiance to the distant Norwegian Crown. Aonghus Mór's first certain appearance in the historical record seems to evince his involvement in aiding native Irish kindreds against the consolidation of Anglo-Irish authority in the north-west of Ireland. Such cooperation could have been undertaken in the context of overseas kindreds like Clann Domhnaill constructing Irish alliances to gain assistance against Scottish encroachment.

Domhnall mac Raghnaill was a Hebridean noble in the late 12th and early 13th centuries. He is the eponymous progenitor of Clan Donald. For this reason some traditions accumulated around him in the later Middle Ages and early modern period. His vast impact on culture and in the centuries remains today. Despite his role as the historical figurehead of one of the world's most famous kindreds and surnames, there is almost no contemporary evidence yielding certain information about his life.