The members of the Peloponnesian league considered themselves betrayed by this treaty, for their hated rival Athens had not been humbled. Corinth was the ringleader in raising disaffection. She determined to create a new league, including Argos, the inveterate foe of Sparta. This state had stood aloof from the war, nursing her strength and biding her time for revenge. When Sparta failed to restore Amphipolis, the war party at Athens, led by Alcibiades, formed an alliance with Argos to reduce Sparta; but this policy alienated Corinth, who refused to act with her trade rival. An Argive attack on Arcadia ended in the fierce battle of Mantinea in 418, in which Sparta won a complete victory. Argos was forced to come to terms, the new league was dissolved and Athens was once more confronted by her combined enemies, her diplomacy a failure and her trump-card, the Sphacterian prisoners, lost. Next year she was guilty of an act of sheer outrage. Her fleet descended on the island of Melos, which had remained neutral, though its inhabitants were colonists from the Spartan mainland close by. Nowhere does the dramatic nature of Thucydides' work stand more clearly revealed than in his account of this incident. He represents the Athenian and Melian leaders as arguing the merits of the case in a regular dialogue, essentially a dramatic device. The Athenian doctrine of Might and Expediency is unblushingly preached and acted upon, in spite of Melian protests; the island was captured, its population being slain or enslaved. Such an act is a fitting prelude to the great disaster which forms the next act of Thucydides' drama. In 416 Athens proceeded to develop her design of subjugating Sicily. Segesta was at feud with Selinus; as the latter city applied to Syracuse for aid, the former bethought her of her ancient alliance with Athens. Next year the Sicilian ambassadors arrived with tales of unlimited wealth to finance an expedition. Nicias, the leader of the peace party, vainly counselled the Assembly to refrain; he was overborne by Alcibiades, whose ambition it was to reduce not only Sicily but Carthage also. When the expedition was about to sail most of the statues of Hermes in the city were desecrated in one night. Alcibiades, appointed to the command with Nicias and Lamachus, was suspected of the outrage, but was allowed to sail. The fleet left the city with all the pomp and ceremony of prayer and ritual, after which it showed its high spirits in racing as far as Aegina. In Sicily itself Hermocrates, the great Syracusan patriot, repeatedly warned his countrymen of the coming storm, advising them to sink all feuds in resistance to the common enemy. He was opposed by Athenagoras, a democrat who, true to his principles, suspected the story as part of a militarist plot to overthrow the constitution. His speech is the most violent in Thucydides, but contains a passage of much value.