He is mentioned being from Frome and also owning estates in modern-day Hertfordshire and Oxfordshire. However, according to the Liber Vitae:Register and Martyrology of New Minster and Hyde Abbey, Winchester, his main landowning interests were in the Winchester area. According to charters dating to the 10th century from the Winchester Archives, where he kept his documents, he was involved in some kind of special service to the royal family and he remained loyal to Eadwig after Edgar the Peaceful's revolt in 957. The archives also reveal that he received grants which were heavily modified or forged by Winchester monks. He is also mentioned in the Chronicles of Abingdon Abbey as being a minister to Eadwig. However, after Edgar came to power in around 959, Æthelgeard ceased to be mentioned. He left a will which read "I, Æthelgeard, grant the estate at Sotwell after my death to my wife for her lifetime, and then for the need of the souls of both of us to the New Minister in Winchester, for them to use and never to alienate."
- Thirsk, Joan (1970). Land, Church, and People: Essays Presented to Professor H.P.R. Finberg. Museum of English Rural Life. p. 16. Retrieved 22 April 2013.
- Abingdon Abbey (1858). Chronicon monasterii de Abingdon. Longman. p. 229. Retrieved 22 April 2013.
- Williams, Ann (3 November 2011). World Before Domesday: The English Aristocracy 871-1066. Continuum International Publishing. p. 97. ISBN 978-1-4411-2118-9. Retrieved 21 April 2013.
- Anglo Saxon wills. CUP Archive. p. 19. ISBN 978-1-00-140620-6. Retrieved 22 April 2013.
- Scragg, D. G. (2008). Edgar, King of the English, 959-975: New Interpretations. Boydell & Brewer Ltd. p. 92. ISBN 978-1-84383-399-4. Retrieved 21 April 2013.
- Keynes, Simon, ed. (1996). The Liber Vitae of the New Minster and Hyde Abbey Winchester. Early English Manuscripts in Facsimile. 26. Rosenkilde and Bagger. pp. 24 n. 84, 86–87. ISBN 87 423 0521 7.