Passage: Following the decisive Battle of Assandun on 18 October 1016, King Edmund signed a treaty with Cnut (Canute) under which all of England except for Wessex would be controlled by Cnut. Upon Edmund's death just over a month later on 30 November, Cnut ruled the whole kingdom as its sole king for almost twenty years.

Question: Which battle resulted in Cnut gaining control of much of England?
Battle of Assandun