King Charles the Bald gives the order to build fortified bridges across the Seine and Loire Rivers, to protect Paris and the Frankish heartland against Viking raids. He hires the services of Weland, a Viking chieftain based on the Somme, to attack the Seine Vikings at their base on the Isle of Oissel. Weland besieges the Vikings—they offer him a huge bribe (6,000 pounds of silver) to let them escape.[3]
Summer – Viking raiders led by Weland sail to England and attack Winchester (the capital of Wessex), which is set ablaze. He spreads inland, but is defeated by West Saxon forces, who deprive him of all he has gained.[5]
March – Robert the Strong is appointed margrave of Neustria by King Charles the Bald. He re-establishes the Breton March, and extends his remit by campaigning against Salomon, duke 'king' of Brittany. Robert hires a combined Seine-Loire fleet for 6,000 pounds of silver, 'before Salomon can ally with them against him'. In return, Salomon enlists 12 Viking ships under the command of Hastein, to raid the county of Maine, which, with Anjou, becomes squeezed between Brittany and Neustria.
Robert the Strong, margrave of Neustria, captures 12 Viking ships and kills their crews. He pays tribute (Danegeld) for keeping the Vikings out of Neustria.[9]
Carloman, eldest son of King Louis the German, revolts against his father. He is captured, but manages to escape to the Ostmark (or 861).
Viking raiders again plunder Dorestad (modern Netherlands), a Frankish port on the mouth of the river Rhine. It thereafter disappears from the chronicles.
Danish Vikings loot along the Rhine. They settle on an island near Cologne, but are driven off by the combined forces of Lothair II and the Saxons.
Spring – Emperor Louis II (the Younger) marches with a Frankish army against Rome. While en route to the papal city, he becomes ill, and decides to make peace with Pope Nicholas I.
Pepin II joins the Vikings in an attack on Toulouse. He is captured while besieging the Frankish city. Pepin is deposed as king of Aquitaine, and imprisoned in Senlis.
Pope Nicholas I orders that all Catholics should abstain from eating the "flesh, blood, or marrow"[22] of warm-blooded animals on Wednesdays and Fridays.[23]
Pope Nicholas I forbids the use of torture in prosecutions for witchcraft (approximate date).
The rival monarchs of Northumbria, Ælla and Osberht, join forces in an attempt to expel the Great Heathen Army, but are defeated in battle by Ivar the Boneless and Halfdan Ragnarsson. Osberht is killed in battle, while Ælla is reportedly captured, before being subject to the blood eagle: a combined method of torture and execution.
Surviving members of the Northumbrian court flee into the northernmost part of the kingdom, Bernicia.
The Council of Constantinople is held (presided over by Patriarch Photius), which anathematizes the use of the Filioque clause in the Creed, and also Pope Nicholas I, for his attacks on the work of Greek missionaries in Bulgaria.
Salomon, duke ('king') of Brittany, leads a joint campaign against the Loire Vikings. He is forced to defend southeastern Brittany unaided, and mobilizes levies raised at Poitiers to defeat the Vikings.
Al-Andalus: The city of Mérida rises against the Umayyad rule. Emir Muhammad I regains control, and has the walls of the city destroyed. He supports the rival creation of Badajoz in retaliation.[26]
^Martínez Diez, Gonzalo (2007). Sancho III el Mayor Rey de Pamplona, Rex Ibericus (in Spanish). Madrid: Marcial Pons Historia. p. 25. ISBN978-84-96467-47-7. JSTORj.ctt6wpw4q.
^John Haywood (1995). Historical Atlas of the Vikings, p. 61. Penguin Books: ISBN978-0-140-51328-8.
^Bóna, István (2000). The Hungarians and Europe in the 9th-10th centuries. Budapest: Historia - MTA Történettudományi Intézete, p. 13. ISBN963-8312-67-X.
^Picard, Christophe (2000). Le Portugal musulman (VIIIe-XIIIe siècle0. L'Occident d'al-Andalus sous domination islamique. Paris: Maisonneuve & Larose. p. 109. ISBN2-7068-1398-9.
^Buhl, Fr. (1986). Bearman, P.; Bianquis, Th.; Bosworth, C. E.; van Donzel, E.; Heinrichs, W. P. (eds.). "al-Ḥasan b. Zayd b. Muḥammad". The Encyclopaedia of Islam (2nd ed.). Brill: 245.
^Kreutz, Barbara M. (1991). Before the Normans: Southern Italy in the ninth and tenth centuries. Philadelphia: University of Pennsylvania Press. p. 43. ISBN0812231015.
^Hill, Paul (2009). The Viking Wars of Alfred the Great. Westholme. pp. 32–6. ISBN978-1-59416-087-5.