Guthrum (, c. 835 – c. 890) was King of East Anglia in the late 9th century. Originally a native of what is now Denmark, he was one of the leaders of the "Great Summer Army" that arrived in Reading during April 871 to join forces with the Great Heathen Army, whose intentions were to conquer the kingdoms of Anglo-Saxon England. The combined armies were successful in conquering the kingdoms of East Anglia, Mercia, and Northumbria, and overran Alfred the Great's Wessex, but were ultimately defeated by Alfred at the Battle of Edington in 878. The Danes retreated to their stronghold, where Alfred laid siege and eventually Guthrum surrendered.