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
Alfred the Great in the following year, with varying outcomes; the places and dates of two of these battles have not been recorded. A successful skirmish at the Battle of Englefield in Berkshire on 31 December 870 was followed by a severe defeat at the siege and Battle of Reading by Ivar's brother Halfdan Ragnarsson on 5 January 871. Four days later, the Anglo-Saxons won a brilliant victory at the Battle of Ashdown on the Berkshire Downs, possibly near Compton or Aldworth. Alfred is particularly credited with the success of this last battle. The Saxons were defeated at the Battle of Basing on