The Kingdom of the Isles comprised the Hebrides, the islands of the Firth of Clyde and the Isle of Man from the 9th to the 13th centuries AD. The islands were known to the Norse as the Suðreyjar, or “Southern Isles” as distinct from the Norðreyjar or Northern Isles of Orkney and Shetland. In Scottish Gaelic, the kingdom is known as Rìoghachd nan Eilean. The historical record is incomplete, and the kingdom was not a continuous entity throughout the entire period. The islands concerned are sometimes referred to as the Kingdom of Mann and the Isles, although only some of the later rulers claimed that title. At times the rulers were independent of external control, although for much of the period they had overlords in Norway, Ireland, England, Scotland or Orkney. At times there also appear to have been competing claims for all or parts of the territory.
Source: Kingdom of the Isles – Wikipedia