sentences:  1200, does speak of his presence in Orkney and his alliance with the joint jarls Arnkel and Erland, sons of Torf-Einarr, but not until his rule in Northumbria was challenged by Olaf (Amlaíb Cuarán).However, a number of later sagas such as the "Separate Saga of St. Olaf" ("c".1225), "Heimskringla", "Egils saga" and "Óláfs saga Tryggvasonar en mesta" assert that he sailed directly to Orkney, where he took the joint jarls into vassalage, collected forces and so set up a base which enabled him to organise several expeditions on overseas territory.