King Hereafter, File Number: ISBN # 0-375-70403-5 @ brother of Hrolf, conqueror of Normandy (AKA Rollo), no parents
The cited information was published by Vintage Books, div. of Random House, New York, 1982 (Ref: brother of Hrolf, conqueror of Normandy (AKA Rollo), no parents) The author/originator was Dorothy Dunnett.