Battle of Rhium

The Battle of Rhium (429 BC) or the battle of Chalcis^[1] was a naval battle in the Peloponnesian War between an Athenian fleet commanded by Phormio and a Peloponnesian fleet composed of contingents from various states, each with its own commander. The battle came about when the Peloponnesian fleet, numbering 47 triremes, attempted to cross over to the northern shore of the Gulf of Patras to attack Acarnania in support of an offensive in northwestern Greece; Phormio's fleet attacked the Peloponnesians while they were making the crossing.

In the battle, the Peloponnesian ships, hampered by the fact that many of them were equipped not as fighting vessels but as transports, circled together in a defensive posture. Phormio, taking advantage of his crews' superior seamanship, sailed around the clustered Peloponnesians with his ships, driving the Peloponnesians closer and closer together until they began to foul oars and collide with each other. The Athenians then suddenly attacked, routing the Peloponnesians and capturing 12 ships.