 It is doubtful whether Rafarta or Fridgerd are Irish, and there are clearly difficulties with the supposed number of generations.Insofar as any conclusions have been reached by historians of Ireland, it appears that the supposed descendants of Cerball left for Iceland in the generation before Donnchad mac Gilla Patraic, towards the end of the tenth century.Given the likely date at which the "Landnámabók" was compiled, this is rather too far in the past for the genealogies to be considered very reliable.