815

By place

Byzantine Empire

• Byzantine–Bulgarian Treaty: Emperor Leo V the Armenian signs a 30-year peace agreement in Constantinople with Omurtag, ruler of the Bulgarian Empire. The Rhodope Mountains become the Byzantine border again, and Leo regains its lost Black Sea cities, after the Bulgars have them demolished.

  Europe

• Hrafna-Flóki Vilgerðarson sets out from the Faroe Islands and discovers Iceland .

  Britain

• King Egbert of Wessex ravages the territories of the remaining British kingdom Dumnonia, known as the West Welsh.

  Asia

• Emperor Saga of Japan is the first sovereign to drink tea, imported from China by monks. The upper classes adopt this beverage for medicinal use.
• July 13 - Wu Yuanheng, Chinese chancellor of the Tang Dynasty, is murdered by assassins of warlord Wu Yuanji, in Chang'an.

  By topic

Religion

• Synod of Constantinople: A council led by patriarch Theodotus I, in the Hagia Sophia, reinstitutes iconoclasm.