Angus Óg, Donald's grandson, commanded the isles from Islay to Ardnamurchan, plus part of Lochaber. He may be regarded as the first MacDonald of the Isles, his son John or Iain, becoming 1st Lord of the Isles. He gained Lewis by royal grant and the southern half of the Outer Hebrides by inheritance through his wife, plus Rhum, and Moidart and Knoydart.
from Neil Grant's book Clans and Tartans of Scotland