Battle of Chalcedon
73 BCE.
Shown on the map at 40.983°, 29.033°.
The Battle of Chalcedon was a land and naval battle between the Roman Republic and King Mithridates VI of Pontus near the city of Chalcedon in 74 BC. It was the first major clash of the Third Mithridatic War. The Roman forces were led by Marcus Aurelius Cotta, one of the consuls for 74 BC, while Mithridates had the overall command of the Pontic forces. The Mithridatic forces were victorious on both land and sea.
Text from the Wikipedia article Battle of Chalcedon (74 BC), licensed CC BY-SA 4.0.