The Battle in Mercia is a military engagement that is the main battle of the Mercian Civil War. It depicts the confrontation between the combined forces of the Kingdom of Wessex and Ragnar's Vikings against the Kingdom of Mercia, led by King Brihtwulf. The event takes place in Season 3 Episode 1, Mercenary.
The Battle of Mercia results in a decisive Vikings/Wessex victory. King Brihtwulf is killed.