It must have been with a high degree of confidence, therefore, that, in 825, Beornwulf marched against the West Saxon’s, but was badly defeated at the battle of Ellandun at the hands of their king Egbert, fought at present day Wroughton near Swindon, Wiltshire.
Some historians have suggested that it was Offa’s defeat of the Welsh and the West Saxons of Wessex that established the Mercian Supremacy, which remained unchallenged until 825 when Egbert of Wessex supported an East Anglian rebellion against Beornwulf of Mercia, whose death at Ellandun effectively brought the Supremacy to an end.
Occupation of the area continued into the early Middle Ages (AD 410–1066) when two battles are understood to have taken place in the area: Breahburh (AD 567), thought to have been fought by Ceawlin of Wessex on the slopes of Barbury Hill, and Ellandun (AD 825) at Elcombe Hall by Egbert of Wessex.