Battle of Tanagra
The Battle of Tanagra took place in 458 BC between Athens and Sparta during the First Peloponnesian War.
When the Phocians made war on the cities of Doris--the traditional homeland of Doric Greeks—the Doric Sparta sent a relief force under the command of Nicodemes, son of Cleombrotus, acting as regent for his under-age nephew, King Pleistoanax. An army of 1,500 Spartan hoplites with 10,000 of their allies entered Boeotia and compelled the submission of Phocis.
Athens, already contemptuous of Spartan treatment and now suspecting her of negotiating with factions within the city to undermine democracy and prevent the construction of the Long Walls, maneuvered to cut off the Spartan army isolated in Boeotia.
Facing either transport through waters controlled by the Athenian navy or a difficult march through the Geraneia mountain passes held by Athenian soldiers supported from Megara, the Spartans decided to wait either for the opening of a safe route home or an outright Athenian assault.
Meeting the Spartans at Tanagra, Athens fielded "their whole army, supported by 1,000 troops from Argos and by contingents from their other allies, making up altogether a force of 14,000 men." Although both sides sustained "great losses," the Spartans were victorious and now able to return home through the mountain passes of the Isthmus.