It was only after that date that democracy was suppressed in the Peloponnesian League, and even then Mantinea remained democratic. In point of fact, it was only when Lysander became the representative of Spartan foreign policy - i.e.
The Phocian levy took part in Epaminondas' inroads into Peloponnesus, except in the final campaign of Mantinea (370-62), from which their contingent was withheld.
This promise he brilliantly fulfilled by routing the forces of the Argive confederacy at the battle of Mantinea (418), the moral effect of which was out of all proportion to the losses inflicted on the enemy.
The Peloponnesian malcontents turned to Argos as a new leader, and an alliance was formed between Argos, Corinth, Elis, Mantinea and the Thraceward towns (420).
On Epaminondas' fourth expedition Sparta was again within an ace of capture, but once more the danger was averted just in time; and though at Mantinea (362 B.C.) the Thebans, together with the Arcadians, Messenians and Argives, gained a victory over the combined Mantinean, Athenian and Spartan forces, yet the death of Epaminondas in the battle more than counterbalanced the Theban victory and led to the speedy break-up of their supremacy.