Before Aethelwulf died, the heathen fleets had already taken to wintering in England, and in the days of his sons the struggle reached its climax. The Viking armies then penetrated into all parts of the island, ravaging and burning unmercifully, and three of the four English kingdoms, Northumbria, Mercia and East Anglia, one after another succumbed to their onslaughts. At times it even looked as if Wessex, the strongest kingdom of them all, would also go under. Many battles went against its armies and more than once all the shires south of the Thames were overrun. In their hour of trial however the West Saxons found a saviour in the famous Alfred, Aethelwulf's youngest son. Under his leadership they again took courage, and at last beat back the invaders and compelled them to confine their settlements to the northern and eastern portions of the country. The England, which emerged from struggle, was an entirely changed England. The four kingdoms of Ecgbert's day had been replaced by a division of the country into two well-marked spheres, one of which was English and Christian while the other was Danish in law and custom, and, in part, heathen. The Danish portion, subsequently known as the Danelaw (Denalagu), had however little political cohesion, being composed of a large number of petty communities under a variety of independent rulers, some styled kings and others "jarls," who were mutually distrustful of each other, whereas the English portion formed a comparatively compact state, looking for guidance and defence to the house of Ecgbert, which alone survived of the four older royal houses. In the hard-fought struggle much had been lost. Letters and the arts had practically perished; Christianity had received a severe shock, and monastic life had either disappeared or become degraded. But in spite of this partial lapse into barbarism much had also been gained, the new settlers being men of vigorous physique and character and eager to develop trade and industry. Their language, too, and their social and legal institutions were not so different, from those of the English as to preclude the hope of amalgamation, and so a situation arose much more favourable than might have been expected for the ultimate unification of the country into a single state, provided that the West Saxon dynasty could retain its vigour and prestige.
The change from Ecgbert to Aethelwulf, just as the period of turmoil began, was by no means a gain for Wessex. The best that can be said for the new king is that he was well-meaning and devout; but he was not the man to intimidate invaders or enlarge his patrimony. He was content to regard Beorhtwulf and Burhred, the kings who ruled in Mercia in his days, as his equals; and, so far as we know, he only once led an army across the Thames, and then not to coerce the Mercians but to assist them in a campaign against the Welsh. Aethelwulf's real bent was towards works of piety, and in later days he was best remembered for his donation to the Church. Landbooks refer to this transaction as a decimatio agrorum, and some have connected it with the institution of
