Óláfr Guðrøðarson (died 29 June 1153) 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 Isles—an archipelagic region roughly incorporating the Hebrides and Mann—was ruled by Guðrøðr Crovan for over two decades until his death in 1095, whereupon his eldest son Lǫgmaðr assumed control. Warring soon broke out between factions supporting Lǫgmaðr's younger brother Haraldr, which led to the intervention and encroachment of Irish power into the region. After a short period of Irish domination, the region lapsed into further conflict which was capitalised on by Magnús Óláfsson, King of Norway, who led two military campaigns throughout the Isles and surrounding Irish Sea region at about the turn of the twelfth century. Magnús dominated these regions until his death in 1103, whereupon control of the Isles appears to have fragmented into chaos once again.
Rather than allow ambitious Irish powers fill the power vacuum, Henry I appears to have installed Óláfr on the throne at some point between 1112 and 1115, about the time that Domnall mac Taidc relocated from the Isles to Ireland. Óláfr is recorded to have spent his youth at Henry I's court, and Óláfr's later religious foundations reveal that he was greatly influenced by his English upbringing. In the second quarter of the eleventh century, Óláfr founded Rushen Abbey, a reformed religious house on Mann. He further oversaw the formation of the Diocese of the Isles, the territorial extent of which appears to reveal the boundaries of his realm. Óláfr is recorded to have had at least two wives: Ingibjǫrg, daughter of Hákon Pálsson, Earl of Orkney; and Affraic, daughter of Fergus, Lord of Galloway. The unions seem to reveal that Óláfr shifted from an alliance with Orkney to that with Galloway. Not long after his marriage to Affraic, one of Óláfr's daughters married Somairle mac Gilla Brigte, Lord of Argyll, an emerging power in the region.
Although Óláfr's reign is recorded to have been peaceful, there is reason to suspect that his own succession was uncertain. In 1152, Guðrøðr travelled to Norway and rendered homage to Ingi Haraldsson, King of Norway. At about this time, the Diocese of the Isles was incorporated within the recently elevated Archdiocese of Niðaróss. Whilst this strengthened Norwegian links with the Isles, it secured the ecclesiastical independence of Óláfr's domain, and safeguard his secular authority in the region. Nevertheless, before Guðrøðr returned to the Isles, three sons of Haraldr confronted Óláfr, and demanded a share of the kingdom before slaying him. Although the three men appear to have taken significant steps to counter military intervention from Galloway, they were soon after crushed by Guðrøðr, who returned to the region strengthened by Norwegian military might. Óláfr's descendants went on to reign as kings of the Isles for over a century.
Óláfr was a member of the Crovan dynasty. He was a son of this family's eponymous ancestor, Guðrøðr Crovan, King of Dublin and the Isles. Others sons of Guðrøðr Crovan include Lǫgmaðr and Haraldr. Óláfr's father appears to have secured the kingship of the Isles in the late 1070s, and to have seized the kingship of Dublin in the early 1090s. Guðrøðr Crovan's downfall came in 1094 when he was forced from Ireland altogether by Muirchertach Ua Briain, King of Munster. There is reason to suspect that Guðrøðr Crovan was driven from Mann as well, since he is recorded to have died on Islay the following year.
According to the thirteenth- to fourteenth-century Chronicle of Mann, Guðrøðr Crovan's eldest son, Lǫgmaðr, succeeded to the kingship of the Isles. The chronicle further reveals that Lǫgmaðr faced opposition from within his own family in the form of a rebellion by his brother, Haraldr. Lǫgmaðr eventually overcame Haraldr, however, and is stated to have had him blinded and emasculated. Afterwards, Lǫgmaðr appears to have faced further opposition in the form of a faction supporting his youngest brother, Óláfr. Apparently unable to overthrow Lǫgmaðr on their own, the dissidents turned to Muirchertach, whose recent conquest of Dublin gave him control of that realm's dominating naval forces.
If the chronicle is to be believed, Óláfr's supporters petitioned Muirchertach to provide a regent from his own kin—the Uí Briain—to govern the Isles until Óláfr was old enough to assume control himself. Such a clause may well have been a condition of Muirchertach's involvement, rather than a request. Nevertheless, the chronicle indicates that Muirchertach installed his nephew, Domnall mac Taidc, upon the throne. Although Domnall had previously opposed Muirchertach over the kingship of Munster, he was the son of Muirchertach's brother, and further possessed strong familial connections with the Isles through his maternal descent from Echmarcach mac Ragnaill, King of Dublin and the Isles. Regardless, the death of Domnall's brother, Amlaíb, recorded by the seventeenth-century Annals of the Four Masters in 1096, suggests that Domnall and the rest of the Meic Taidc faced significant opposition in the Isles, possibly in the form of Lǫgmaðr's adherents. Domnall's reign appears to have been brief. The chronicle's account of warfare on the island in about 1097–1098 fails to mention him at all, a fact which seems to be evidence that he had lost control by then.
Probably late in 1097, Magnús Óláfsson, King of Norway turned his attention towards the Isles, and sent a certain Ingimundr into the region to take control on his behalf. Unfortunately for Magnús, Ingimundr was soon after slain on Lewis and Harris by leading Islesmen. The following year Magnús took matters into his own hands, and led an invasion-fleet of his into the area. As the invaders successfully carved their way through the Isles towards Mann, Lǫgmaðr was evidently overcome and captured. From Mann, the Norwegians campaigned against the English in Anglesey. Although Magnúss saga berfœtts, within the thirteenth century Heimskringla, places this particular episode in the context of Norwegian conquest, it is likely that Magnús had merely assumed the same protector role that Óláfr's father had once filled with Gruffudd ap Cynan, King of Gwynedd. Magnús gained the submission of Galloway, and may have consolidated his campaign through a treaty with Edgar, King of Scotland.
Magnús overwintered in the Isles, and left for Norway in the summer. He made his return to the region, nearly four years later, in 1102 or 1103. After reestablishing himself on Mann, Magnús entered into a marital alliance with Muirchertach formalised through the marriage between Magnús's young son, Sigurðr, and Muirchertach's young daughter, Bjaðmunjo. The fact that Magnús intended to return to Norway reveals that Muirchertach benefited to most from the arrangement, although the alliance appears to have bound the kings against a common enemy in the region, Domnall Mac Lochlainn, King of Cenél nEógain. Unfortunately for Muirchertach, and his long-term ambitions in the Isles, Magnús was slain in Ulster in 1103, and Sigurðr immediately repudiated his bride and returned to Norway. Although Muirchertach was able to regain control of Dublin and still had held considerable influence in the Isles, Magnús' death left a vacuum which neither Muirchertach nor Domnall Mac Lochlainn could fill.