Rǫgnvaldr Óláfsson (died 1249)

Rǫgnvaldr Óláfsson (died 30 May 1249) was a mid-thirteenth-century King of Mann and the Isles who was assassinated after a reign of less than a month. As a son of Óláfr Guðrøðarson, King of Mann and the Isles, Rǫgnvaldr Óláfsson was a member of the Crovan dynasty. When his father died in 1237, the kingship was assumed by Haraldr Óláfsson. The latter was lost at sea late in 1248, and the following year Rǫgnvaldr Óláfsson succeeded him as king.

Only weeks after gaining the kingship, Rǫgnvaldr Óláfsson was slain by a knight named Ívarr and his accomplices. The kingship was then seized by Haraldr Guðrøðarson, Rǫgnvaldr Óláfsson's first cousin once removed, suggesting that the killers and the new king had colluded together. The assassination, therefore, appears to have been a continuation of the vicious family feud that had engulfed the Crovan dynasty since the late twelfth century, when Rǫgnvaldr Óláfsson's father and Haraldr Guðrøðarson's grandfather first contested the kingship of the Isles.