England in 871 was still a fractured land of kingdoms often in conflict with one another. Wessex had emerged as the most powerful kingdom and its location in the island’s southwest had protected it from the brunt of the Danish invasions. The Danes had repeatedly assaulted Britain’s eastern coast since 789, but had intensified their invasion forces by 865 and expanded into western Britain by 870.
In 871 the Great Summer Army of the Danes, led by a Viking king known as Bagsec, landed in Britain. They joined forces with the Great Heathen Army, a Viking army that had overrun much of eastern and central England. Together the Viking forces turned their attention to Wessex. They managed to entrench themselves and build an encampment at Reading, an ideal location. They were protected on two sides by the Thames and Kennet rivers. A rampart was constructed to shield them from the west.
From their encampment at Reading the Danes began a campaign to overtake Wessex. In their first venture, they sought to overtake Englefield, a nearby village. A Saxon force under the command of Æthelwulf, the Ealdorman of the shire, met the Danes and soundly defeated them, driving them back to the camp at Reading. Four days later, Æthelwulf and his Saxon contingent were joined by the main West Saxon army, led by King Æthelred and his brother, Alfred the Great.
The combined Saxon army marched against the Danish encampment at Reading on 4 January 871, as is recounted in the Anglo-Saxon Chronicle. Interestingly, the Chronicle’s account is the first historical evidence of a settlement at Reading, and it is thought that the name ‘Reading’ derives from the Anglo-Saxon tribe known as the Readingas, which means Reada’s People in Old English. Unfortunately for the Saxons, they were repulsed at the Battle of Reading. The Anglo-Saxon Chronicle put it this way: “and there was much slaughter on either hand, Ealdorman Æthelwulf being among the slain; but the Danes kept possession of the field.”
Though the Saxons were repulsed at the Battle of Reading, they continued to battle the Danes throughout the winter of 871. They won a famous victory at the Battle of Ashdown, but when King Æthelred died, his brother Alfred took the throne. He would eventually be known as Alfred the Great, and much of his reign was consumed by conflict with the invading Danes.