Battle of Devina
1279 CE.
Shown on the map at 42.917°, 26.450°.
The Battle of Devina occurred on 17 July 1279 near the small fortress of Devina, close to the modern town of Kotel, Burgas Province, south-eastern Bulgaria. Ivailo of Bulgaria attacked the Byzantine army sent to help his rival for the crown Ivan Asen III.
Text from the Wikipedia article Battle of Devina, licensed CC BY-SA 4.0.