Battle of Pelekanon
1329 CE.
Shown on the map at 41.010°, 29.150°.
The Battle of Pelekanon, also known by its Latinised form Battle of Pelecanum, occurred on June 10–11, 1329, between an expeditionary force by the Byzantines led by Andronikos IIl and an Ottoman army led by Orhan I. The Byzantine army was defeated, with no further attempt made at relieving the cities in Anatolia under Ottoman siege.
Text from the Wikipedia article Battle of Pelekanon, licensed CC BY-SA 4.0.