Dictionary of National Biography, 1885-1900/Ælfthryth (d.929)
ÆLFTHRYTH, Lat. Eltrudis (d. 929), was a younger daughter of King Ælfred. She was brought up in her father's court with her brother Eadward. Asser dwells on the care with which the brother and sister were educated. Ælfthryth learnt all that was held fitting for people of high birth to know. She studied the Psalms and English books, and, above all, the English songs which her father loved so well. Ælfthryth married Baldwin II, count of Flanders, a violent and greedy man. She received Chippenham and two other estates in Wiltshire by her father's will. In 912 she gave Lewisham with its dependencies, Greenwich and Woolwich, to the abbey of St. Peter at Ghent. Her husband, Baldwin, died in 915, and was buried in the abbey of St. Bertin. Two years after his death Ælfthryth had his body moved to Ghent and buried in the church of St. Peter. She died in 929, and was laid beside her husband. She had two sons and two daughters. Her elder son, Arnulf, succeeded his father as count of Flanders. Fifth in descent from Arnulf was Matilda, daughter of Baldwin V and wife of William the Conqueror. Ælfthryth forms, therefore, an important link in the genealogy of the royal family of England. Her second son, Adelulf, was count of Boulogne.
[Asser, de Rebus gestis Ælfredi; Æthelweard, Chron. i.; Sigebert, Chron. 918, in Recueil des Historiens, &c. viii. 310; Frodoard, Hist. iv. 10; L'Art de vérifier, &c. xiii. 282; Dugdale, Monasticon, vi. 987.]