On January 4, 871 AD, the Danes surprised the people of Wessex by arriving on horseback in a lightning raid that swiftly took the town of Reading.
There, the invaders, who had already conquered much of land in the North and East of England, made a fortified camp, using the Thames and Kennet rivers to protect their flanks, and throwing up a rampart on the Western edge of the town.
Three days after their arrival, a party of Danes rode out towards nearby Englefield, where a West Saxon force under the command of Æthelwulf, the Ealdorman of the shire, was waiting for them. In the ensuing Battle of Englefield many of the Danes were killed, and the rest driven back to Reading.
Four days later, Æthelwulf had been joined by the main West Saxon army, led by King Æthelred and his brother, Alfred the Great.
The entire Saxon force marched on Reading.
The assault was directed mainly at a gateway through the ramparts, and fierce and bloody fighting followed, before the attack was repulsed. Among the many dead of both sides was Æthelwulf.
The Saxon forces were forced to retreat, allowing the Danes to continue their advance into Wessex but it was not fo long, because after the battle, Æthelred and Alfred reformed their army, and a few days later won a famous victory at the Battle of Ashdown, forcing the Danes to retreat to Reading once more.
Two weeks later the Danes won the Battle of Basing, and then, on 22 March, the Battle of Marton. In April Æthelred died, to be succeeded by Alfred.
The Danish army remained in Reading until late in 871, when they retreated to winter quarters in London, and much of King Alfred’s 28-year reign was taken up with the Danish conflict, and so, the long campaign to keep Wessex from falling to the Norsemen had begun.