Guthrum

Guthrum (Old English: Guðrum, c. 835 – c. 890) was King of East Anglia in the late 9th century. Originally a native of 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, Northumbria, and parts of Mercia, 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.

Under the terms of his surrender, Guthrum was obliged to be baptised as a Christian to endorse the agreement and then leave Wessex. The subsequent Treaty of Alfred and Guthrum set out the boundaries between Alfred and Guthrum's territories, as well as agreements on peaceful trade and the weregild value of its people. This treaty is seen as the foundation of the Danelaw. Guthrum ruled East Anglia under his baptismal name of Æthelstan until his death.