Æthelstan was the son of Æthelfrith, an Ealdorman who held lands in Somerset, Berkshire, and Middlesex.
The lands King Æthelstan gave him had mostly been part of the Danelaw which had only been forced out of the area after the Battle of Tempsford in Bedfordshire fifteen years earlier in 917.
[3] Æthelstan and his family were supporters of the monastic reforms of Saint Dunstan which introduced the Benedictine rule to Glastonbury.
Byrhtferth referred to "Ealdorman Æthelstan, whom the elders and all the populace called 'Half-King', since he was a man of such authority that he was said to maintain the kingdom and its rule with his advice to the king".
[8] People associated with Æthelstan's family include Ealdorman Byrhtnoth, whose defeat at the Battle of Maldon is commemorated in verse.