Somerled, a nobleman of Irish descent, Lord of Arygll, was asked for help by the chiefs of the Isles to free them from the tyrant Godred IV. They offered to make his eldest son Dugall king over the Isles.
On January 6th 1156 Somerled, using 80 galleys of his own design, defeated the Norse in a fierce sea battle off the north coast of Islay, and eventually ruled over Mull, Call, Tiree, Colonsay, Islay, Gigha, Kintyre, Knapdale, Lorne and Argyll.
In 1164 he was killed while fighting against Malcolm IV of Scotland, and it is thought he was buried at Saddell Abbey in Kintyre.
On the death of Somerled his inheritance was divided among his son Dugall and his two grandsons Ruari and Donald, sons of Somerled's son Reginald (Ranald). The descendants of Donald were given Islay, and by the 14th century, as a result of wise policy decisions and marriage alliances, they had become the dominant lineage.
The support given to Robert Bruce by Angus Og of Islay, who was one of his commanders at Bannockburn, is an example of these policy decisions. This connection with the Stewart dynasty was continued during the long reign of John, first Lord of the Isles.