Æthelred of Wessex of Mercia, appealed to him for help against the Vikings. Æthelred and his brother, the future Alfred the Great, led a West Saxon army to Nottingham, but there was no decisive battle, and Burgred bought off the Vikings. In 874 the Vikings defeated Burgred and drove him into exile. In 870 the Vikings turned their attention to Wessex, and on 4 January 871 at the Battle of Reading, Æthelred suffered a heavy defeat. Although he was able to re-form his army in time to win a victory at the Battle of Ashdown, he suffered further defeats on 22 January at
Ailill mac Dúnlainge (died 871) his camp was attacked by the Laigin who were at first successful, but in a counter-attack they were put to flight. Ailill's name is not connected with these events which state that Muiredach mac Brain was the King of Leinster who fought the forces of Cerball. The "Fragmentary Annals" give a lengthy account of this event and state that Cerball met up with the high king's forces at Belach Gabrán (the pass of Gowran in east-central Osraighe) but both forces then retired and the hostages of the Laigin were not taken. In 871 Ailill was killed by the Vikings of