The Battle of Chalcedon was a naval battle in 74 BC during the Third Mithridatic War

Third Mithridatic War

The Third Mithridatic War was the last and longest of three Mithridatic Wars fought between Mithridates VI of Pontus and his allies and the Roman Republic...

. It ended in Pontian victory.

After resuming the war, consul Marcus Aurelius Cotta took Roman fleet into the Bosphorus. Outside the harbour of Chalcedon

Chalcedon

Chalcedon , sometimes transliterated as Chalkedon) was an ancient maritime town of Bithynia, in Asia Minor, almost directly opposite Byzantium, south of Scutari . It is now a district of the city of Istanbul named Kadıköy...

 he was beaten by the Pontian fleet; Roman ships sought refuge inside the harbour, but to no avail: the Pontians made their way into the port, where they destroyed or captured Romans' fleet. After the victory, Mithridates

Mithridates VI of Pontus

Mithridates VI or Mithradates VI Mithradates , from Old Persian Mithradatha, "gift of Mithra"; 134 BC – 63 BC, also known as Mithradates the Great and Eupator Dionysius, was king of Pontus and Armenia Minor in northern Anatolia from about 120 BC to 63 BC...

 moved against the Roman controlled town of Cyzicus

Cyzicus

Cyzicus was an ancient town of Mysia in Anatolia in the current Balıkesir Province of Turkey. It was located on the shoreward side of the present Kapıdağ Peninsula , a tombolo which is said to have originally been an island in the Sea of Marmara only to be connected to the mainland in historic...

, which he besieged. This led to the battle of Cyzicus

Battle of Cyzicus (74 BC)

The Siege of Cyzicus was fought in 73 BC between armies of Mithridates VI of Pontus and the Roman-allied citizens of Cyzicus in Mysia and Roman Republican forces under Lucius Licinius Lucullus. It was a decisive Roman victory....

.