"Æthelstan A" (/ˈæθəlstænˈeɪ/) is the name given by historians to an unknown scribe who drafted charters (or diplomas), by which the king made grants of land, for King Æthelstan of England between 928 and 935. They are an important source for historians as they provide far more information than other charters of the period, showing the date and place of the grant, and having an unusually long list of witnesses, including Welsh kings and occasionally kings of Scotland and Strathclyde.
The "Æthelstan A" charters commence shortly after King Æthelstan conquered Northumbria in 927, making him the first king to rule the whole of England. The diplomas give the king titles such as "King of the English" and "King of the Whole of Britain", and this is seen by historians as part of a rhetoric which reflected his master's claim for a new status, higher than previous West Saxon kings.
The diplomas are written in elaborate Latin known as the hermeneutic style, which became dominant in Anglo-Latin literature from the mid-tenth century and a hallmark of the English Benedictine Reform. Scholars vary widely in their views of his style, which has been described as "pretentious" and "almost impenetrable", but also as "poetic" and "as enduringly fascinating as it is complex".
"Æthelstan A" ceased to draft charters after 935, and his successors returned to a simpler style, suggesting that he was working on his own rather than being a member of a royal scriptorium.
After the death of Bede in 735, Latin prose in England declined. It reached its lowest level in the ninth century, when few books and charters were produced, and they were of poor quality. King Æthelstan's grandfather, Alfred the Great (871–899) embarked on an extensive programme to improve learning, and by the 890s the standard of Latin in charters was improving. Few charters survive from the reigns of Alfred and his son, Edward the Elder (899–924), and none from 909 to 925. Up to then charters had generally been plain legal documents, and King Æthelstan's early diplomas were similar.