Æthelred II of England

Definition and stakes

Charles Oman, Albert Pollard, Samuel Gardiner, Spencer Walpole and Hugh Chisholm 1911 Encyclopædia Britannica (1911)

His power was something far greater than that of the Guthrums and Anlafs of an earlier generation, and—in the end of his life at least—he was aiming at political conquest, and not either at mere plunder or at finding new settlements for his followers. But if the strength of the invader was greater than that of his predecessors, Æthelred also was far better equipped for war than his ancestors of the 9th century. He owned, and he sometimes used—but always to little profit—a large fleet, while all England instead of the mere realm of Wessex was at his back.
Source: Wikisource

J. Franck Bright A History of England, Period I. Mediæval Monarchy

Eadward’s first difficulty was with his cousin Æthelwulf, the son of Alfred’s elder brother Æthelred. This prince claimed the throne. He landed in England, was driven to Northumbria, where he was chosen king, and then, in company with Eohric, the King of East Anglia, marched up the Thames to Cricklade. He was however defeated, and with his ally killed by a portion of the English army near the Ouse. The consequence was the renewal of the acknowledgment of the supremacy of Wessex by Guthrum II. of East Anglia.
Source: Gutenberg

Portrait of Sarah Orne Jewett Sarah Orne Jewett The Normans; told chiefly in relation to their conquest of England

He was apt to be too busy at home; but William's affairs were in good order, and his cousin of England was a feeble man and more than half a Norman; besides, he had no heir, and in course of time the English throne would lack a proper king. The idea of such a holiday might have pleased the anxious suitor of Matilda of Flanders, too, and have beguiled the hard time of waiting. Nobody stopped to remember that English law gave no right of succession to mere inheritance or descent. Ralph the Timid was Æthelred's grandson; but who would think of making him king instead of such a man as William?
Source: Gutenberg

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