 According to the twelfth-century "Historia regum Anglorum", Owain Foel assisted his Scottish counterpart, Máel Coluim mac Cináeda, against the English at the Battle of Carham in 1018.Either Owain himself, or his like-named grandfather Owain ap Dyfnwal, King of Strathclyde, or else their ultimate royal successor Owain Foel may be identical to Owain Caesarius, a legendary figure associated with an assemblage of apparent tenth-century monuments at Penrith collectively known as The Giant's Grave.The nearby site of Castle Hewin (), a place name meaning "Owain's castle" (derived from ), may well be named after the same man.