In the following year Ethelbald died, and after a year's anarchy was succeeded by Offa. He was not only a great warrior, but a great statesman, and combined a series of conquests with a series of judicious marriage alliances, until he had almost succeeded in making himself king over all England. His most glorious wars were those against the Welsh, whom he drove back from the Severn to the Wye. He built a large dyke from the mouth of the Wye to the mouth of the Dee to keep them back, called Offa's dyke. Offa was reverenced on the Continent almost as much as in England, and we even find him corresponding on terms of equality with the Emperor Charles the Great, known to romance as Charlemagne. Offa was a warm friend of the Church; he created a temporary archbishopric at Lichfield as a rival to York and Canterbury, and founded the Abbey of St. Albans. The power of Mercia, however, depended almost entirely on the personal abilities of her kings, and ended with Cenwulf, who reigned from 796 to 815. After his death it speedily collapsed, partly owing to the failure of the royal line, partly owing to the rising power of Wessex, and partly also owing to devastating raids of the Danes, who had already begun to make their appearance in Britain. CHAPTER IV. RISE OF WESSEX AND OF THE SOCIAL SYSTEM OF ENGLAND. Ceawlin and his Successors--Cedwalla--Ina--Subjection to Mercia--Accession of Egbert--He subdues his Rivals--His Wars with the Welsh and Danes--Land-owning System--Local Assemblies--The Hundred Moot--The Shire Moot and its Business--Methods of Trial and Punishments--The Wergild--The Witena-gemot--Its Powers--The King--Class Distinctions--The Church. Hitherto the rise of the kingdom of Wessex has been left out of sight in these pages; but as we are approaching the reign of the great king Egbert, it is necessary to trace the steps by which a great power had been slowly consolidated in the West under a series of able kings. We have already mentioned Ceawlin, the third of the sovereigns of the West Saxons. This prince greatly added to his authority and possessions. Besides defeating the Welsh in numerous battles, and conquering a large district north of the Thames, he seized upon the kingdom of Sussex after the death of Cissa, defeated the King of Kent, and was suspected of entertaining the ambitious project of reducing all England under his sceptre. But his subjects, headed by his nephew, Ceolric, rose against him, and met him in battle at Wodensbury. Being defeated, Ceawlin ended his days in exile. This collapse lost to the kingdom of Wessex all the country which had been annexed to the north of the Thames. Ceolric, his nephew, succeeded him; he died in 597. This last-named prince was followed by his brother, Ceolwulf, who defeated the South Saxons, and died in 611.