850s

Europe

• February 1 – King Ramiro I dies in his palace at Santa María del Naranco (near Oviedo), after an 8-year reign. He is succeeded by his son Ordoño I, as ruler of Asturias.
• Danish Viking raiders, led by King Rorik, conquer Dorestad and Utrecht (modern-day Netherlands). Emperor Lothair I recognizes him as ruler of most of Friesland.
• King Louis II, the eldest son of Lothair I, is crowned joint emperor by Pope Leo IV at Rome, and becomes co-ruler of the Middle Frankish Kingdom.

Britain

• King Kenneth I (also called Kenneth MacAlpin) of Alba (modern Scotland) invades Northern Northumbria during the period of 850–858, burning Dunbar and Melrose.
• The Pillar of Eliseg is erected by King Cyngen ap Cadell of Powys (Wales), as a memorial to his great-grandfather Elisedd ap Gwylog (or Eliseg) (approximate date).

Japan

• May 6 – Emperor Ninmyō dies after a 17-year reign. He is succeeded by his son Montoku, as the 55th emperor of Japan.

India

• It is hypothesized that sometime around 850 a group of Buddhist pilgrims travelling through a valley near Roopkund (modern India) were killed when caught out in the open in a sudden hailstorm. Their remains were discovered in 1942.

Mesoamerica

• Uxmal becomes the capital of a large state in the Puuk hills region of northern Yucatán (modern Mexico). The city is connected by causeways (sakbe) to other important Puuk sites, such as K'abah, Sayil, and Labna (approximate date).

Food and Drink

• Coffee is discovered (according to legend) by the Ethiopian goatherder Kaldi in East Africa, who notices that his goats become energetic after chewing the red berries from certain wild bushes (approximate date).

Religion

• April 22 – Gunther becomes archbishop of Cologne (modern Germany).
• June 18 – Perfecto, a Christian priest in Muslim Córdoba, is executed (beheaded) after he refuses to retract numerous insults he made about the prophet Muhammad.

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