 Cerball, known to Icelanders' sagas as Kjarvalr Írakonungr, raided Munster and obtained allies and mercenaries from among the Norse and Norse-Gaels of southern Ireland.The Fragmentary Annals of Ireland, a combination of annals and history written in the 11th century for Donnchad mac Gilla Pátraic king of Osraige and Leinster, say that the expedition of 854 was led by Cerball on Máel Sechnaill's orders, although Máel Sechnaill himself appears also to have raided into Munster that year.It is reported that Cerball joined forces with Ivarr, a king of the "Dark foreigners"