The Spartan king Agis concluded the first campaign with a truce, without explaining his actions to the army or his allies.

As a result, Spartans directed their anger towards Agis, who avoided a 10,000 drachmas fine and the destruction of his house, by promising to redeem himself with a victory.

[2] The ephors placed Agis under the supervision of ten symbouloi (advisers), whose consent was required for whatever military action he wished to take.

Enemy control of the town would mean that the Spartans would be unable to move out of their home city and would result in the demise of the Peloponnesian coalition that fought the Archidamian War.

Agis marched the whole of the Spartan army, including neodamodes and everyone who was able to fight in Sparta into Tegea where he was joined by his allies from Arcadia.

However, the northern army could not arrive at the scene in time, as they had not expected the call and would have to pass through enemy territory (Argos and Orchomenus).

Agis took advantage of the withdrawal and sent a sixth of his army, with the youngest and the oldest hoplites home to guard Sparta proper.

Agis, who was desperate for a victory to redeem his embarrassment at Argos, charged ahead; but according to Thucydides, when the armies had closed to a stone's throw, "one of the elder Spartans"[3] (the symboulos Pharax, according to Diodorus[4]) advised him not to try to correct one error (his former defeat) with another.

Donald Kagan considers it an ill-advised move and gives credit to the two captains for disobeying orders that could have lost the battle for the Spartans.

Agis did not pursue the Athenians but turned the center and right around and marched to give support to his hard-pressed left.

The Mantineans were chased off the field with heavy losses while the Spartans allowed the Argive Thousand to escape virtually unharmed.