Clan Macdonald of Sleat, sometimes known as Clan Donald North and in Gaelic Clann Ùisdein , is a Scottish clan and a branch of Clan Donald — one of the largest Scottish clans. The founder of the Macdonalds of Sleat was Ùisdean, or Hugh, a 6th great-grandson of Somerled, a 12th-century Lord of the Isles (Rì Innse Gall). The clan is known in Gaelic as Clann Ùisdein ("children of Ùisdein"), and its chief's Gaelic designation is Mac Ùisdein ("son of Ùisdean"), in reference to the clan's founder. Both the clan and its clan chief are recognised by the Lord Lyon King of Arms, who is the heraldic authority in Scotland.