The Modern Facsimile trireme Olympias

Athenian admiral recognized for his skillful use of triremes in the early years of the Peloponnesian War. Little is known of the family or early career of Phormio, son of Asopios. By 440 b.c. he appears to have obtained the Athenian military office of strategos, when he shared command of 40 ships sent to reinforce a blockade of the island city-state of Samos, a rebellious member of the Athenian Empire. Some years after the successful siege of Samos, possibly in 437 b.c., Phormio commanded 30 ships on an expedition to the western Greek district of Acarnania and enlisted the Acarnanians as allies of the Athenians. In 432 b.c. he completed the investment of Potidaea, another defiant member of the Athenian alliance. By these actions Phormio helped strengthen the Athenian alliance on the eve of its great war with the Sparta and the Peloponnesian League.

Once the war with Sparta commenced, Phormio played a major role in Athenian naval operations. In 430 b.c. he led 20 Athenian triremes into the Gulf of Corinth and undertook a blockade of the city of Corinth, an important ally of Sparta. In the next year, just outside the gulf, Phormio demonstrated his superior tactical abilities when he decisively defeated a larger Peloponnesian fleet of 47 ships. Shortly after this victory, as he reentered the Gulf to protect his base at Naupactus, Phormio lost 9 of his ships to the Peloponnesian fleet, then reinforced to a total of 77 vessels. With only 11 ships remaining at his disposal, Phormio nevertheless managed to prevent an attack on Naupactus and with a brilliant counterattack dispersed the Peloponnesian fleet. The detailed descriptions of these two engagements by the Athenian historian Thucydides are among the most important sources for modern understanding of ancient Greek naval tactics.

After leading a second expedition into Acarnania from Naupactus during the winter of 429–428 b.c., Phormio returned to Athens. In 428 b.c. Phormio was unavailable for another command. This may be attributed either to his illness or death, possibly from the plague that ravaged Athens, or to his loss of civic rights following a judgment against him in the examination to which Athenian commanders were normally subject at the expiration of their commands.

Hornblower, Simon. A Commentary on Thucydides. Vol. 1. Oxford, UK: Oxford University Press, 1991.
Kagan, Donald. The Archidamian War. Ithaca, NY: Cornell University Press, 1974.
Morrison, John S., John F. Coates, and N. Boris Rankov. The Athenian Trireme. 2d ed. Cambridge, UK: Cambridge University Press, 2000.
Thucydides. History of the Peloponnesian War. Various editions.