871

Millennium:	1st millennium
Centuries:	8th century – 9th century – 10th century
Decades:	840s 850s 860s – 870s – 880s 890s 900s
Years:	868 869 870 – 871 – 872 873 874

871 by topic
Politics
State leaders – Sovereign states
Birth and death categories
Births – Deaths
Establishment and disestablishment categories
Establishments – Disestablishments

Events

Nine battles are fought between the Danes and Wessex. Of two of them the place and date are not recorded, the others are:
- 31 December, 870 – Englefield
- 4 January – Reading
- 8 January – Ashdown
- 22 January – Battle of Basing
- 22 March – Merton
- May – Battle of Wilton
Alfred the Great succeeds as king of Wessex after Ethelred's death.
Reading, England is occupied by the Norse.
After the battle at Wilton, peace is made, with the Danes and Alfred each governing part of England.
Rhodri Mawr ('the Great') of Gwynedd inherits Seisyllwig, thus uniting most of Wales under his rule.
Louis II captures Bari, the headquarters of the Saracens.
Alfred makes Winchester his capital.
An incomplete marriage contract, dated to October 6 of this year, is the earliest dated document in the Cairo Geniza.
Tønsberg, the oldest surviving town in the Nordic countries, is founded.
Svatopluk I becomes king of Great Moravia.