Battle of the Echinades
1427 CE.
Shown on the map at 38.367°, 21.067°.
The Battle of the Echinades was fought in 1427 among the Echinades islands off western Greece between the fleets of Carlo I Tocco and the Byzantine Empire. The battle was a decisive Byzantine victory, the last in the Empire's naval history, and led to the consolidation of the Peloponnese under the Byzantine Despotate of the Morea.
Text from the Wikipedia article Battle of the Echinades (1427), licensed CC BY-SA 4.0.