Guthrum or Guðrum (died c. 890), christened Æthelstan on his conversion to Christianity in 878, was King of the Danish Vikings in the Danelaw. He is mainly known for his conflict with Alfred the Great.
Guthrum, founder of the Danelaw
It is not known how Guthrum consolidated his rule as king over the other Danish chieftains of the Danelaw (Danish-ruled territory of England), but by 874 he was able to wage a war against Wessex and its King, Alfred.
In 875, the Danish forces, then under Guthrum and Halfdan Ragnarsson, divided, Halfdan's contingent returning north to Northumbria, while Guthrum's forces went to East Anglia, quartering themselves at Cambridge for the year.
By 876, Guthrum had acquired various parts of the kingdoms of Mercia and Northumbria and then turned his attention to acquiring Wessex, where his first confrontation with Alfred took place on the south coast. Guthrum sailed his army around Poole Harbour and linked up with another Viking army that was invading the area between the Frome and Piddle rivers which was ruled by Alfred. According to the historian Asser, Guthrum won his initial battle with Alfred, and he captured the castellum as well as the ancient square earthworks known as the Wareham, where there was a convent of nuns.
Alfred successfully brokered a peace settlement, but by 877 this peace was broken as Guthrum led his army raiding further into Wessex, thus forcing Alfred to confront him in a series of skirmishes that Guthrum continued to win. At Exeter, which Guthrum had also captured, Alfred made a peace treaty, with the result that Guthrum left Wessex to winter in Gloucester.
On Epiphany, 6 January 878, Guthrum made a surprise night-time attack on Alfred and his court at Chippenham, Wiltshire. It being a Christian feast day the Saxons were presumably taken by surprise—indeed it is possible that Wulfhere, the Ealdorman of Wiltshire, allowed the attack either through negligence or intent, for on Alfred's return to power later in 878 Wulfhere was stripped of his role as Ealdorman.
Alfred fled the attack with a few retainers and took shelter in the marshes of Somerset, staying in the small village of Athelney. Over the next few months he built up his force and waged a guerrilla war against Guthrum from his fastness in the fens. After a few months Alfred called his loyal men to Egbert's Stone, and from there they travelled to Edington to fight the invaders.
Defeat by Alfred
Guthrum's hopes of conquering all of Wessex came to an end with his defeat at the hands of Alfred at the Battle of Edington in 878. At Edington, Guthrum’s entire army was routed by Alfred's and fled to their encampment where they were besieged by Alfred's fyrd for two weeks. According to the Anglo-Saxon Chronicle, Guthrum’s army was able to negotiate a peace treaty known as the Treaty of Wedmore. The Anglo-Saxon Chronicle recorded the event:
- “Then the raiding army granted him (Alfred) hostages and great oaths that they would leave his kingdom and also promised him that their king (Guthrum) would receive baptism; and they fulfilled it. And three weeks later the king Guthrum came to him, one of thirty of the most honourable men who were in the raiding army, at Aller - and that is near Athelney - and the king received him at baptism; and his chrism loosing was at Wedmore.” 
Conversion to Christianity and peace
Under the Treaty of Wedmore, the borders dividing the lands of Alfred and Guthrum were established, Guthrum converted to Christianity, and he took on the Christian name Æthelstan with Alfred as his godfather.
Guthrum upheld his end of the treaty and left the boundary that separated the Danelaw from English England unmolested. Guthrum, although failing to conquer Wessex, turned towards the lands to the east that the treaty had allotted under his control. Guthrum withdrew his army from the western borders facing Alfred's territory and moved eastward before eventually settling in the Kingdom of Guthrum in East Anglia in 879. He lived out the remainder of his life there until his death in 890. According to the Annals of St Neots, a chronicle compiled in Bury St Edmunds, Guthrum was buried at Headleage, which is usually identified as Hadleigh, Suffolk.
Guthrum appears in several works of fiction, including:
- G. K. Chesterton's poem The Ballad of the White Horse.
- C. Walter Hodges' juvenile historical novels The Namesake and The Marsh King.
- Bernard Cornwell's first three novels of The Saxon Stories series The Last Kingdom, and The Pale Horseman, and The Lords of the North.
- Collingwood, M. A. and Powell, F. Y. Scandinavian Britain (New York: Society for Promoting Christian Knowledge, 1908), p. 94.
- Anglo Saxon Chronicle Trans. by M. J. Swanton (New York, Routledge: 1996).
- Davis, R. H. C. From Alfred the Great to Stephen (London, The Hambledon Press: 1991) p. 48.
- Dumville, David; Lapidge, Michael (1985). The Annals of St Neots with Vita Prima Sancti Neoti, The Anglo-Saxon Chronicle: a Collaborative Edition. Cambridge. ISBN 978-0-85991-117-7.
| King of East Anglia