865

By place

Europe

• King Louis the German divides the East Frankish Kingdom among his three sons. Carloman receives Bavaria. He gives Saxony to Louis the Younger and Swabia to Charles the Fat. Louis arranges marriages into the local aristocracy, for his sons to hold important territories along the frontiers.
• King Lothair II, threatened with excommunication, takes back his first wife, Teutberga. She expresses her desire for an annulment, but this is refused by Pope Nicholas I.
• Boris I, ruler of the Bulgarian Empire, suppresses a revolt, and orders the execution of 52 leading boyars, along with their whole families.

  Britain

• The Great Heathen Army of Vikings, led by Ivar the Boneless and Halfdan Ragnarsson, invades East Anglia. King Edmund of East Anglia buys peace with a supply of horses.
• Viking king Ragnar Lodbrok is captured by the Northumbrians in battle, and killed by being thrown into a pit filled with poisonous snakes, on the orders of King Ælla of Northumbria.
• Autumn - King Æthelberht of Wessex dies after a 5-year reign, and is buried at Sherborne Abbey. He is succeeded by his brother Æthelred I, as ruler of Wessex.

  Abbasid Caliphate

• Caliphal Civil War: An armed conflict starts between the rival Muslim caliphs al-Musta'in and al-Mu'tazz. They fight to determine who takes control over the Abbasid Caliphate.

  By topic

Religion

• Kassia, a Byzantine abbess and hymnographer, dies. She is one of the first Early Medieval composers of many hymns.