BY the end of the ninth century two great Mercian kings, Æthelbald and Offa, had established a political ascendency that made the rulers of Mercia the dominating personalities in English affairs, even though the realm of Wessex and the once mighty state of Northumbria still held themselves aloof. It was during this period of Mercian supremacy that the first recorded viking raids, the sporadic plunderings of Norwegian pirates (p. 4), took place; but after the appearance of vikings near Dorchester and the attacks upon Lindisfarne and Jarrow, England knew no more of the pirates for a period of forty years, and when they began once again to plague this country the power and territories of the English kingdoms had altered. Northumbria remained a rich but sorry state, enfeebled by a turmoil of civil wars; the great kingdom of Mercia had dwindled to only half its former size; Wessex had expanded to a large and prosperous realm that now embraced all of England south of the Thames. The men of Essex had also submitted to the West Saxons; but the East Anglians, who had broken away from Mercia, were ruled by their own king as an independent realm.
RISE OF THE KINGDOM OF WESSEX
The man who had accomplished this aggrandizement of Wessex, who had conquered West Wales ( Cornwall and Devon), routed the Mercians, and put his own son to rule over the sub- kingdom of Kent, was the ætheling Ecgbert, son of one of the petty kings of Kent. He had been driven out of England by Offa and Beorhtric of Wessex, but on the death of Beorhtric in 802 he returned to be elected king of Wessex in his place. It was in 825 that Mercia collapsed and the growing power of the southern kingdom was transformed into an assured supremacy.
The viking attacks begin again in 834. It was the year of a great Danish attack upon Frisia (p. 194), and many of the Danes who set out then, and later, to harry that country and the French coast also determined to try their fortunes in England. They first appeared at the Thames mouth, where they ravaged the island of Sheppey, but two years later there was another raid,