Viking Age by a Viking leader called Bagsecg and his five earls. Aided by the Great Heathen Army (which had already overrun much of England from its base in Jorvik), Bagsecg's forces, and Halfdan's forces (through an alliance), the combined Viking forces raided much of England until 871, when they planned an invasion of Wessex. On 8 January 871, Bagsecg was killed at the Battle of Ashdown along with his earls. As a result, many of the Vikings returned to northern England, where Jorvic had become the centre of the Viking kingdom, but Alfred of Wessex managed to keep them out of
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