874

By place

Europe

• Salomon, duke of Brittany, is murdered by a faction which includes his son-in-law Pascweten and Gurvand, son-in-law of late ruler Erispoe. After Salomon's death they divide the country, and Pascweten and Gurvand co-rule Brittany.
• Svatopluk I, ruler of Great Moravia, concludes a peace treaty at Forchheim. He is able to expand his territories outside the Frankish sphere, and subjugates the Vistulans.
• Ingólfr Arnarson arrives from Norway, as the first permanent Viking settler in Iceland. He builds his homestead and founds Reykjavík. The settlement of Iceland begins.

Britain

• The Danish Vikings drive King Burgred of Mercia into exile, and sack Tamworth. They conquer his kingdom and install his political opponent, Ceolwulf II, as sub-king.
• Autumn – The Great Heathen Army splits into two bands; Halfdan returns with his forces to Northumbria, along with his brother Ubba, where he establishes a new base on the River Tyne.
• Amlaíb Conung, the first Norse 'king' of Dublin, is killed in Scotland, during a campaign against his rival Constantin I.
• November – Frost begins in Scotland, and lasts until April 875.

China

• Huang Chao, a salt privateer, joins forces with Wang Xianzhi to raise a rebel army at Changyuan. The uprising further weakens the Tang dynasty, which is already weakened by natural disasters such as severe droughts and floods.

By topic

Religion

• March 13 - The remains of Saint Nikephorus I are interred in the Church of the Holy Apostles, in Constantinople.
• The monastery of Sevanavank, located on the shore of Lake Sevan, is founded.
• Muhammad al-Mahdi, the child of the eleventh Shi'i Twelver Imam Hasan al-Askari, begins his Imamate. His first period of occultation, known as the Minor Occultation, also begins.