 It may be possible, then, to synchronise the activities of Ingware and Halfdene in England as recorded in the English annals with the activities of Ímar and Albann in Ireland and Laithlind as recorded in the Irish annals; nevertheless, some discrepancies remain, and this has led a number of modern historians to reject the identity of Ingware and Ímar (though not necessarily that of Halfdene and Albdann).In 870 Amlaíb and Ímar besieged Ail Cluaithe, or Dumbarton, the capital of Strathclyde; they captured the stronghold following a four-month siege, and returned to Dublin in 871 with a great deal of plunder.Later that year they stormed the fortress of Dún Sobairche or Dunseverick in County Antrim with the assistance of the Cenél nEógain, whose leader was the High King Áed Findliath.