Guthrum was a Viking leader and king of the Danes in the late 9th century. He is best known for his role in the conflicts with the Anglo-Saxon kingdoms, particularly during the reign of King Alfred the Great of Wessex. After several battles, Guthrum and his forces were eventually defeated at the Battle of Edington in 878. Following his defeat, Guthrum converted to Christianity and was baptized, taking the name Aethelstan. He established the Danelaw, a region in England where Danish law and customs were practiced. His reign marked a significant period of Viking influence in England.