History of the Peloponnesian War

But the Athenians went out against the Lacedaemonians with their whole force and with one thousand Argives and contingents of the several allies, the whole body amounting to fourteen thousand men.

And they undertook the expedition against them because they believed that they were at a loss how to get through, and partly too on a suspicion of a plot to overthrow the democracy.

The forces of the Athenians were strengthened by some Thessalian cavalry, who came in accordance with the terms of the alliance, but they deserted to the Lacedaemonians in the course of the action.

The battle took place[*](456 B.C.) at Tanagra in Boeotia, and in it the Lacedaemonians and their allies were victorious, and there was much slaughter on both sides.