These were reinforced by ships from the settled Danes of East Anglia and Northumbria, some of this contingent sailed round the coast to besiege a fortified place (known as a burh) and Exeter, both in Devon.
He left his son-in-law Æthelred, Lord of the Mercians and ealdormen Æthelhelm, Æthelnoth, and others in charge of defending various towns and cities from the rest of the Viking army.
As the political system in Francia (part of modern day France) was in turmoil the Vikings concentrated their efforts there as the raiding was more profitable.
[9][10][11] By late 892, the leadership in Francia had become more stable and the Vikings were finding it difficult to make progress there too, so they again attempted a conquest of England.
[10][16] Alfred had been on his way to relieve his son at Thorney when he heard that the Northumbrian and East Anglian Danes were besieging Exeter and an unnamed[g] burh on the North Devon shore.
The Anglo-Saxon Chronicle says that "after many weeks had passed, some of the heathen [Vikings] died of hunger, but some, having by then eaten their horses, broke out of the fortress, and joined battle with those who were on the east bank of the river.
[10][16] The annals say that the Vikings came up the Severn from the Thames making the most likely candidate for the location of the battle as present-day Buttington,[18] Welshpool in the county of Powys, Wales.
[19] The Vikings who had taken to their ships after Alfred's arrival, at Exeter, sailed along the south coast and attempted to raid Chichester, a burh according to the Burghal Hidage, manned by 1,500 men.
[16] According to the Anglo-Saxon historian Æthelweard writing nearly a hundred years later, "Hastein made a rush with a large force from Benfleet, and ravaged savagely through all the lands of the Mercians, until he and his men reached the borders of the Welsh; the army stationed then in the east of the country gave them support, and the Northumbrian one similarly.
The famous Ealdorman Æthelhelm made open preparation with a cavalry force, and gave pursuit together with the western English army under the generalship of Æthelnoth.