Sechnaill later the same year. These alliances were by no means permanent. In 860 Cerball was allied with Máel Sechnaill in a campaign against Áed Findliath of the Northern Uí Néill, while Olaf and Ivar has allied themselves with Áed. In 870, however, Cerball and Áed appeared as allies in Leinster. Máel Sechnaill had more success as high king than his predecessors Niall Caille and Conchobar Donnchada (Duncan) in dealing with the south, and forced Munster into submission in 858 and as noted above, Osraige in 859. He also asserted control over Ulaid, Leinster and Connacht, and was in his obituary in the Annals of Ulster described as ri h-Erenn uile, king of all Ireland. The last years of his reign he had however experienced serious opposition from his Uí Néill kinsmen of Ailech and Brega, allied with the Norse of Dublin. Byrne notes: "Máel Sechnaill's unprecedented success in achieving the high-kingship of all Ireland was marred by the chronic complaint of Irish politics: having united the Ulaid, Munster, Osraige, Connacht and Leinster, he was attacked at the end of his reign by a combination of Uí Néill kings." Áed Findliath was king of Ailech and the leading king within the Northern Uí Néill. After the death of Máel Sechnaill he is counted in the regal lists as high king, following the established scheme where this alternated between Cenél nEógain in the north and Clann Cholmáin of Mide. His kingship was disputed though, and he did not come close to being an actual king over Ireland. He could count some successes against the Norse, however, most notably burning all the Norse longports in the north in 866. Áed seems to have used the opportunity while Olaf was involved in warfare in Pictland, presumably bringing a large contingent of the Norse forces in Ireland with him. The Vikings never managed to establish permanent settlements in the north. Ó Corráin observes: "Ironically, [Áed Findliath's] success may have held back the economic development of the north and ultimately prevented the growth of port towns like those on the east and south coasts, on which the Leinster and Munster kings subsequently depended for much of their wealth." The last report of Olaf is when he and Ivar returned to Dublin in 871 from Alba. Ivar died in 873. In his obituary, the Annals of Ulster call Ivar "king of the Norsemen of all Ireland