The combined forces of the Northmen and Wessex sail up a river into Mercia to conquer it for Princess Kwenthrith on behalf of King Ecbert. They are confronted by two armies, each on one bank of the river. The smallest is commanded by Brihtwulf, who proclaimed himself King of Mercia. Ragnar decides to attack Brihtwulf first, as Burgred has a considerable force on the other bank, and there is no bridge in sight to allow him to come to his uncle's aid. Brihtwulf's army are overwhelmed by Viking and Wessex forces. Before he can flee, he is dragged from his horse and killed by Floki, who picks up his crown.
At the camp, Kwenthrith asks for her uncle's head, which she angrily starts to stab. When Ragnar asks why she hated her uncle so much, she tells her uncle raped her many times when she was young.
- Brihtwulf appears to be based on a Mercian King Beorhtwulf (reigned 840-852 AD). Unlike the series depiction of he, Beorhtwulf was alleged relative of Prince Wigstan (reigned 840 AD), not the uncle of Princess Cwenthryth (Kwenthrith) and King Burgred. Burgred is the relative of Beorhtwulf;
- Brihtwulf forced marriage the mother of Wigstan the Queen Aelfflaed (reigned 840 AD) with his relative King Burgred (reigned 852-874 AD).
|Season three appearances|
|Mercenary||The Wanderer||Warrior's Fate||Scarred||The Usurper|
|Born Again||Paris||To the Gates!||Breaking Point||The Dead|