ECGBERT or ECGBERHT (d. 839), king of the West Saxons, son of Ealhmund, succeeded to the throne in 802 on the death of Beorhtric. It is said that at an earlier period in his life he had been driven out for three years by Offa and Beorhtric. In 815 Ecgbert ravaged the whole of the territories of the West Welsh, which probably at this time did not include much more than Cornwall. In 825 he joined the men of Devon against the West Welsh, who were again defeated at Camelf ord. The next important occurrence in the reign was the defeat of Beornwulf of Mercia at Ellandun, probably near Winchester, in 825. Ecgbert sent his son Aethelwulf against Kent ; he drove Baldred, king of Kent, across the Thames, and Kent, Surrey, Sussex and Essex sub mitted to Wessex; while the East Anglians, who slew Beornwulf shortly afterwards, acknowledged Ecgbert as overlord. In 829 the king finally conquered Mercia, and Northumbria, which ac cepted him as overlord. Ecgbert was the first king to hold the whole of England under his overlordship. He also increased his power by reversing the Mercian policy of resisting the authority of the archbishops, and by making an agreement of perpetual alliance with the church of Canterbury. In 83o he led a success ful expedition against the Welsh. In 836 he was defeated by the Danes, but in 838 he entirely routed them and their allies the West Welsh at Hingston Down (Hengest dune) in Cornwall. Ecgbert died in 839, after a reign of 37 years, and was succeeded by his son Aethelwulf.
See Chronicle (ed. Earle and Plummer, 1899) ; W. de G. Birch, Cartularium Saxonicum . Also a paper by Sir H. H. Howorth in Numismatic Chronicle, 3rd series, vol. xx. pp. 66-87 (reprinted separately, 1 goo) , where attention is called to the peculiar dating of several of Ecgbert's charters, and the view is put forward that he remained abroad considerably later than the date given by the Chronicle for his accession. On the other hand a charter in Birch, Cart. Sax., purporting to date from 799, contains the curious statement that peace was made between Coenwulf and Ecgbert in that year.