Battle of Ongal (Fidem Pacis)

The Battle of Ongal was fought in AD 678 on the field of Ongal, in the region of the Danube delta. The battle had enormous significance for Balkan history as it led to the creation of the First Bulgarian Empire and the loss of Roman authority over the area.

Background
Throughout the 7th century the Eastern Roman Empire was constantly at war with the Western Empire, with Persia, and with itself in the form of rebellions and usurpations. The result was that, although it managed to survive all assaults, by the end of the century the empire had been significantly weakened by the enormous loss of manpower and by the loss of trade.

The Bulgars had until recently dwelt north of the Black Sea as part of a confederation, but with the death of their khan Kubrat, and under increasing pressure from the Khazars, they united under Kubrat's second son Asparukh and began a great migration west. Some Bulgar tribes wished to split from the confederation, but they were cowed into obediance by Asparukh's execution of his brothers and rivals. By 667 the Bulgar Khanate had arrived in Roman Moesia and begun to make a new home.

In 668 the Roman Empire signed a peace treaty with the West, freeing up troops to dislodge the Bulgars. Emperor Constantine IV personally led a large army drawn from all over the Empire, including Slavic allies, and attacked the fledgling Bulgar state. Asparukh gathered his people and withdrew to the island of Peuce in the Danubian delta, where he made his stand.