837 CE
Halley's Comet passes approximately 5 million km from Earth, its closest ever approach. The Slavs in the vicinity of Thessaloniki revolt against the Byzantine Empire. Theophilos undertakes an evacuation of some Byzantine captives, who are settled in trans-Danubian Bulgaria. Byzantine–Arab War: Emperor Theophilos leads a massive Byzantine expeditionary force into Mesopotamia. He sacks the cities Arsamosata and Sozopetra — which some sources claim as the birthplace of Abbasid caliph Al-Mu'tasim — and forces Melitene to pay tribute.
Conflict & Security
- The city of Naples (modern Italy) is attacked by Saracens from Egypt demanding an annual payment (approximate date).source
- The Slavs in the vicinity of Thessaloniki revolt against the Byzantine Empire. Theophilos undertakes an evacuation of some Byzantine captives, who are settled in trans-Danubian Bulgaria.source
- Presian I, ruler (khan) of the Bulgarian Empire, sends his prime-minister Isbul against the Smolyani (a Slavic tribe in Byzantine territory near the Struma River). The Bulgarian army campaigns along the Aegean coasts, and conquers most of Thrace and Macedonia, including the fortress city of Philippi, as recorded in the Presian Inscription.source
Religion & Belief
- Byzantine–Arab War: Emperor Theophilos leads a massive Byzantine expeditionary force into Mesopotamia. He sacks the cities Arsamosata and Sozopetra — which some sources claim as the birthplace of Abbasid caliph Al-Mu'tasim — and forces Melitene to pay tribute.source
Science & Discovery
- April 10 – Halley's Comet passes approximately 5 million km from Earth, its closest ever approach.source
Births
Deaths
- Hugh of Tours, Frankish noblemansource
- Li Zaiyi, general of the Tang Dynasty (b. 788)source
- Peter of Atroa, Byzantine abbot (b. 773)source
- Maxentius, patriarch of Aquileiasource
- King Drest IX dies after a 3-year reign. He is succeeded as ruler of the Picts by his cousin Eóganan mac Óengusa.source
- Antony I, patriarch of Constantinoplesource