The Battle of Ellandun was fought between Egbert of Wessex and Beornwulf of Mercia. It effectively ended Mercian Supremacy over the southern kingdoms of Anglo-Saxon England and established West Saxon dominance in southern England. It is described as "one of the most decisive battles of English history". Ecgberht's power peaked in 829, when he occupied Mercia and secured recognition of his supremacy by the Northumbrians, making him temporarily the overlord of all England. Mercian independence was restored in the following year by Wiglaf, who achieved a significant recovery of Mercian prestige and was even able to extend his power over Berkshire. The independence of East Anglia and the West Saxon conquest of the south-east proved irreversible and Mercia never regained the primacy it had enjoyed in the century before Ellandun.