History of the Peloponnesian War

The Argives had been aware of the preparations of the Lacedaemonians from the first, and when the latter were on the march to Phlius where they intended to join the rest, they now took the field themselves. And the Mantineans came to their aid with their own allies and three thousand Elean hoplites.

As they were going forward they came upon the Lacedaemonians at Methydrium in Arcadia. Each party took position on a hill, and the Argives prepared to fight with the Lacedaemonians, thinking to find them still isolated; but Agis, rousing up his force during the night and eluding detection, marched to Phlius to join the rest of the allies.

The Argives, perceiving this, set out at daybreak, marching first to Argos and then taking the road to Nemea, where they expected the Lacedaemonians with their allies to come down.

Agis, however, did not take the way they were expecting him to follow, but giving the word to the Lacedaemonians, Arcadians, and Epidaurians, he advanced by a more difficult route and descended to the Argive plain. The Corinthians, Pellenians, and Phliasians advanced by another steep road; while the Boeotians, Megarians and Sicyonians had been told to come down by the road to Nemea, where the Argives were posted, in order that if the Argives should attack their main force as it advanced into the plain, they might hang on their rear and use their cavalry against them.

Having, then, so disposed his troops, Agis came down into the plain and proceeded to ravage Saminthus and other places.