The author of the Chronicon Æthelweardi is commonly identified with the ealdor-man of the western shires who signed charters from 973–98 and played an important political role particularly in King Æthelred's England. Ealdorman Æthelweard is also known as the patron of Abbot Ælfric, as the addressee of Ælfric's famous preface to his translation of Genesis and of his Old English preface to his Lives of Saints; that is, we know him as a person who took great interest in religious texts written in or translated into the vernacular. The Chronicon was written in Latin, although it was mainly based on the Anglo-Saxon Chronicle. The reason for his choice of language may be determined from the prologue to his Chronicon, from which it becomes clear that he wrote it for his kinswoman Mathilda (949–1011), abbess of Essen, whose grandmother Eadgyth, daughter of King Edward the Elder, had been married to Emperor Otto I. We may assume that Mathilda's native tongue was Old Saxon, a variety of Low German that was closely related to West Saxon English.