The Danes harried the whole country, burnt the monasteries, and annexed Norfolk and Suffolk as a second Danish kingdom.

East Anglia, too, disappears for a while from our English annals.
Lastly, the Danes turned against Mercia and Wessex.

In 871, a host under Bagsecg and Halfdene came to Reading, which belonged to the latter territory, when the local ealdorman engaged them and won a slight victory.

Shortly afterward the West Saxon king AEthelred, with his brother AElfred, came up, and engaged them a second time with worse success.

Three other bloody battles followed, in all of which the Danes were beaten with heavy loss; but the West Saxons also suffered severely.
For three years the host moved up and down through Mercia and Wessex; and the Mercians stood by, aiding neither side, but "making peace with the host" from time to time.