Battle of Demetrias
1270 CE.
Shown on the map at 39.350°, 22.942°.
The Battle of Demetrias was a sea engagement fought at Volos in Greece in the early 1270s between a Byzantine fleet and the assembled forces of the Latin barons of Euboea (Negroponte) and Crete. The battle was fierce, and initially in favour of the Latins, but the timely arrival of Byzantine reinforcements tipped the scale, resulting in a crushing Byzantine victory.
Text from the Wikipedia article Battle of Demetrias, licensed CC BY-SA 4.0.