775

By place

Byzantine Empire

• September 14 - Emperor Constantine V dies while on a campaign in Bulgaria. In his 34-year reign he has suppressed monasticism and image worship, restored aqueducts, revived commerce, and repopulated Constantinople. He is succeeded by his 25-year-old son Leo IV, who continues Constantine's campaigns against the Bulgars and Muslim Arabs.

  Europe

• Saxon Wars: King Charlemagne holds a major assembly at Quierzy. He leads a Frankish army into Saxony to retake the castrum of Syburg, then rebuilds and garrisons fortified Eresburg. He reaches the Weser at a place called Braunsberg, where the Saxons stand for battle, but are defeated when Frankish troops cross the river.
• Westphalian Saxons, probably commanded by Widukind, cross the Weser and fight an inconclusive battle at Hlidbeck. Charlemagne claims victory, but perhaps in reality suffers a setback. He reunites his forces and inflicts a real defeat upon the Saxons, seizing considerable booty and taking hostages, though Widukind escapes.
• Autumn - Charlemagne retakes the Hellweg along the Lippe Valley, establishing communications between Austrasia, Hesse and Thuringia. It is used as a trade route under Frankish supervision.
• The German city of Giessen is founded.

  Africa

• Andalusian merchants set up an emporium on the Maghreb coast at Ténès. It is early evidence of the revival of the maritime trade in the Western Mediterranean, after the chaos of the early 8th century.

  Arabian Empire

• April 25 - Battle of Bagrevand: The Abbasids put an end to an Armenian rebellion. Muslim control over Transcaucasia is solidified, while several major Armenian nakharar families, notably the Mamikonian, lose power and flee to the Byzantine Empire.
• Caliph al-Mansur dies after a 21-year reign, in which he has made Baghdad the residence of the Abbasid Caliphate. He is succeeded by his son al-Mahdi.
• At around this time, Baghdad becomes the largest city in the world, taking the lead from Chang'an, capital of China.

  Asia

• Tibet subdues her Himalayan neighbors, and concludes a boundary agreement with the Chinese Tang dynasty.
• King Dharmapala begins his reign of Bengal.

  By topic

Astronomy

• A 1.2% growth of carbon-14 concentration recorded in tree rings suggests that a very strong solar storm may have hit the earth, in either 774 or 775.