Which 991 CE battle beside River Blackwater is the inspiration for an Old English poem of the same name?
The Homecoming of Beorhtnoth Beorhthelm's Son:  It is a work of historical fiction, inspired by the Old English poem "The Battle of Maldon". Battle of Maldon: The Battle of Maldon took place on 10 or 11 August 991 CE near Maldon beside the River Blackwater in Essex, England, during the reign of Æthelred the Unready.
i don't know