853

By place

Byzantine Empire

• May 22 - A Byzantine fleet sacks and destroys the port city of Damietta, located on the Nile Delta in Egypt. A large quantity of weapons and supplies intended for the Emirate of Crete are captured.

Europe

• Danish Vikings attempt to subjugate the Curonians on the shoreline of the Baltic Sea, but they are repulsed. King Olof leads Swedish Vikings in retaliation, and attacks the towns of Seeburg and Apuolė.
• Viking marauders in Gaul sail eastward from Nantes without opposition, and reach Tours. The monasteries at Saint-Florent-le-Vieil and Marmoutier are ravaged.
• King Charles the Bald bribes Boris I, ruler of the Bulgarian Empire, to form an alliance against his brother Louis the German, with Rastislav of Moravia.
• Gauzbert, count of Maine, is killed during an ambush by citizens of Nantes, in revenge for the death of Lambert II.

Britain

• King Burgred of Mercia appeals to Æthelwulf, king of the West Saxons, for help against the rebellious Welsh king Rhodri the Great. Æthelwulf agrees to send help, and Wales is subdued as far north as Anglesey.
• Burgred marries Æthelwulf's daughter Æthelswith, during a ceremony at the royal estate at Chippenham.

China

• Tuan Ch'eng-Shih, Chinese author and scholar during the Tang Dynasty, publishes Miscellaneous Offerings from Yu-yang.

By topic

Religion

• The Fraumünster Church in Zürich is founded by Louis the German.