Anglo-Saxon Britain by Grant Allen

The death of Dunstan was the signal for the breaking down of the artificial kingdom which he had held together by the mere power of his solitary organising capacity. AEthelred, the son of Eadgar (who succeeded after the brief reign of his brother Eadward), lost hopelessly all hold over the Scandinavian north. At the same time, the wicking incursions, intermitted for nearly a century, once more recommenced with the same vigour as of old. Even before Dunstan's death, in 980, the pirates ravaged Southampton, killing most of the townsfolk; and they also pillaged Thanet, while another host overran Cheshire. In the succeeding year, "great harm was done in Devonshire and in Wales; " and a year later again, London was burnt and Portland ravaged. In 985, AEthelred, the Unready, as after ages called him, from his lack of _rede_ or counsel, quarrelled with AElfric, ealdormen of the Mercians, whom he drove over sea.

The breach between Mercia and Wessex was thus widened, and as the Danish attacks continued without interruption the redeless king soon found himself comparatively isolated in his own paternal dominions.