Aethelred ruled as Lord of the Mercians from c. 881 to 911 and was a key military leader in the fight against Viking conquest and settlement in England. To defend Mercia, he allied himself to the powerful Kingdom of Wessex under the leadership of Alfred the Great (r. 871-899) and later married Alfred's daughter, Aethelflaed, to strengthen their alliance.
This is a companion discussion topic for the original content at https://www.worldhistory.org/Aethelred,_Lord_of_the_Mercians/.