1911 Encyclopædia Britannica/Æthelred I.
ÆTHELRED I., king of Wessex and Kent (866-871), was the fourth son of Æthelwulf of Wessex, and should, by his father's will, have succeeded to Wessex on the death of his eldest brother Æthelbald. He seems, however, to have stood aside in favour of his brother Æthelberht, king of Kent, to whose joint kingdoms he succeeded in 866. Æthelred's reign was one long struggle against the Danes. In the year of his succession a large Danish force landed in East Anglia, and in the year 868 Æthelred and his brother Alfred went to help Burgred, or Burhred, of Mercia, against this host, but the Mercians soon made peace with their foes. In 871 the Danes encamped at Reading, where they defeated Æthelred and his brother, but later in the year the English won a great victory at "Æscesdun." A fortnight later they were defeated at Basing, but partially retrieved their fortune by a victory at "Maeretun" (perhaps Marden in Wiltshire), though the Danes held the field. In the Easter of this year Æthelred died, perhaps of wounds received in the wars against the Danes, and was buried at Wimborne. He left a son, Æthelwold, who gave some trouble to his cousin Edward the Elder, when the latter succeeded to the kingdom. Æthelweard the historian was also a descendant of this king.
Authorities.—The Saxon Chronicle, sub ann.; Birch, Cartul. Saxon. vol. ii. Nos. 516-526; D.N.B., s.v.; Eng. Hist. Review, i. 218-234.