Question: What is the date of death of Ragnall Guthfrithson's father?
Sentence (from "Ragnall mac Gofraid"): Ragnall and Gofraid flourished at a time when the Kingdom of the Isles seems to have suffered from Orcadian encroachment at the hands of Sigurðr Hlǫðvisson, Earl of Orkney.
Relevant evidence: No