Óláfr Guðrøðarson was a twelfth-century King of Mann and the Isles. As a younger son of Guðrøðr Crovan, King of Dublin and the Isles, Óláfr witnessed a vicious power struggle between his elder brothers in the aftermath of their father's death. At some point, the young Óláfr was entrusted to the care of Henry I, King of England, and like the contemporaneous Scottish monarchs, Alexander I and David I, Óláfr appears to have been a protégé of the English king. As King of the Isles, Óláfr contracted marital alliances with neighbouring maritime rulers. Although he appears to have overseen successful military operations to reclaim the northernmost territories once controlled by his father, he may have witnessed the loss of authority in Galloway as well. Like his counterpart David I, Óláfr was a reformer and moderniser of his realm. However, his four-decade reign ended in abrupt disaster when he was assassinated by three nephews in 1153. Following the ensuing power struggle, Óláfr's son Guðrøðr overcame the kin-slayers, and assumed the kingship of the Kingdom of the Isles.

The Kingdom of the Isles was a Norse-Gaelic kingdom comprising the Isle of Man, the Hebrides and the islands of the Clyde from the 9th to the 13th centuries AD. The islands were known to the Norsemen 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 territory is sometimes called the Kingdom of Mann and the Isles, although only some of the later rulers claimed that title. The historical record is incomplete, and the kingdom was not a continuous entity throughout the entire period. 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. The islands have a total land area of over 8,300 square kilometres (3,205 sq mi) and extend for more than 500 kilometres (310 mi) from north to south.