1 October – King Æthelwulf marries as his second wife the teenage Judith of Flanders at Verberie and she is crowned queen of Wessex. He returns to Wessex but Æthelbald retains rule of part of the kingdom.
4 February – death of Ceolnoth, Archbishop of Canterbury. He is succeeded by Æthelred.
871
The English retreat onto the Berkshire Downs. The Great Heathen Army, led by the Danish Viking kings Halfdan Ragnarsson and Bagsecg, march out after the Saxons. Six pitched battles are fought between the Vikings and Wessex. Of two of them the place and date are not recorded, the others are given here:
4 January – Battle of Reading: A West Saxon force, under the command of King Æthelred I and his brother Alfred, is defeated by the Vikings at Reading. Among the many dead on both sides is Æthelwulf of Berkshire. The Saxon troops are forced to retreat, allowing the Vikings to continue their advance into Wessex.[4][9]
8 January – Battle of Ashdown: The West Saxons, led by Æthelred I and Alfred, gather on the Berkshire Downs. The Vikings under the command of Halfdan and Bagsecg occupy the high ground, but are successfully attacked by Alfred's men. During the battle Alfred breaches the shield wall formation.[1][10]
22 January – Battle of Basing: The West Saxon army, under the command of Æthelred I, is defeated at Basing; the Vikings, led by Halfdan, are victorious; Æthelred is forced to flee and regroup, leaving behind precious winter supplies.[10]
23 April – King Æthelred of Wessex dies and is succeeded by his brother Alfred the Great.[1] Æthelred is buried at Wimborne Minster; while Alfred is making the funeral preparations, his army is again defeated.
May – Battle of Wilton: Alfred the Great is defeated by the Vikings at Wilton (along the southern side of the River Wylye), and is forced to makes peace with them, probably paying them Danegeld, and establishes his capital at Winchester.[11]
Autumn – Vikings withdraw from Reading and sail down the River Thames to raid the Mercian port of Lundenwic (modern-day London) and overwinter here.[10] Viking armies go on to colonize areas of north, central and eastern England, later becoming known as the Danelaw.
Vikings capture Exeter but their supply fleet is destroyed in a storm off Swanage[12] and they are driven out by Alfred and settle in the Five Boroughs.[1]
877
Approximate date – Saxons invaders kill Rhodri the Great, Prince of Gwynedd, and his son (or brother) Gwriad.[3][13]
Princes of southern Wales acknowledge Alfred as their overlord.[1]
879
Guthrum relocates to East Anglia where he will rule under his baptismal name of Æthelstan.[1][12]
886
Alfred restores London to Mercia.
Alfred signs a treaty with Guthrum, granting the territory between the Thames and the Tees to the Vikings; later known as the Danelaw.[1]
Tradition of the Ripon hornblower begins, continuing for at least a thousand years.[14]
888
30 June – death of Æthelred, Archbishop of Canterbury. He is succeeded by Plegmund.
Probable date – Shaftesbury Abbey is founded as a convent by Alfred who installs his daughter Æthelgifu as first abbess.[15]
890
The Welsh ruler Anarawd ap Rhodri, King of Gwynedd, makes the first ceremonial visit to an English court, that of Alfred.
Approximate date – Alfred begins to commission and undertake a series of translations into Old English, beginning with his own version of Pope Gregory I's Pastoral Care.
892
Danish Vikings invade again, under the leadership of Hastein.[1]
A Danish Viking army under Hastein moves to a burh at Benfleet (Essex); this camp is captured by the Saxons while the army is out raiding and Hastein is forced to retreat to Shoebury.[16]
Autumn – Danish Vikings under Hastein take the city of Chester,[1] after a rapid march from East Anglia. Alfred the Great destroys their food supplies, forcing them to move into Wales.[16]
Asser of Sherborne writes The Life of King Alfred (Vita Ælfredi regis Angul Saxonum).[1]