Three periods of Anglo-Saxon history are particularly well documented: the reigns of Alfred the Great, Æthelred (the Unready), and Edward the Confessor. Much has been written about the reigns of Alfred and Edward, but, by comparison, little attention has been paid to the reign of Æthelred.

An examination of the sources for Æthelred's reign shows that he and his councillors have been victims of much malign propaganda. In the period immediately after his death, Æthelred's failure to combat and defeat invading armies was contrasted unfavourably with the dynamic actions of his son, King Edmund Ironside, and it was suggested that God had used the invasions to punish the English nation because the murder of King Edward the Martyr, in 978, had gone unpunished. After the Norman Conquest, this suggestion was taken further. It was said that God had punished the English by allowing a Danish conquest and then a Norman conquest of the country because of the murder of King Edward the Martyr, a murder which had been instigated by his (step) mother Queen Ælfthryth, who wanted her son, Æthelred, to become king. This malign propaganda led to an assessment of the king and his reign which can be summarised in the words of Eadmer: