Ecgberht, King of Wessex

Ecgberht was King of Wessex from 802 until his death in 839. His father was Ealhmund of Kent. In the 780s Ecgberht was forced into exile Charlemagne's court in the Frankish empire by Offa of Mercia and Beorhtric of Wessex, but on Beorhtric's death in 802 Ecgberht returned home and took the throne. 
Little is known of the first 20 years of Ecgberht's reign, but it is thought that he was able to maintain the independence of Wessex against the kingdom of Mercia, which at that time dominated the other southern English kingdoms. In 825 Ecgberht defeated Beornwulf of Mercia, ended Mercia's supremacy at the Battle of Ellandun, and proceeded to take control of the Mercian dependencies in southeastern England. In 829 he defeated Wiglaf of Mercia and drove him out of his kingdom, temporarily ruling Mercia directly. Later that year Ecgberht received the submission of the Northumbrian king at Dore. 
Ecgberht was unable to maintain this dominant position, and within a year Wiglaf regained the throne of Mercia. However, Wessex did retain control of Kent, Sussex, and Surrey; these territories were given to Ecgberht's son Æthelwulf to rule as a subking under Ecgberht. When Ecgberht died in 839, Æthelwulf succeeded him; the southeastern kingdoms were finally absorbed into the kingdom of Wessex after the death of Æthelwulf's son Æthelbald in 860. Ecgbert's descendants ruled Wessex and, later, all of England continuously until 1013.