King of Wessex (802–39). In 825 he won a decisive victory near Swindon, bringing Mercian supremacy to an end, and annexed Kent, Essex, Surrey, and Sussex. In 829 Mercia itself fell to Egbert and Northumbria acknowledged his rule. By the time of his death, Mercia had become independent again, but his reign foreshadowed the supremacy that Wessex later secured over all England.