In 425 a most important event took place. As an Athenian squadron was proceeding to Sicily it was forced to put in at Pylos, where many centuries later Greece won a famous victory over the Turks. Demosthenes, though he had no official command, persuaded his comrades to fortify the place as a base from which to harry Spartan territory. It was situated in the country which had once belonged to the Messenians who for generations had been held down by the Spartan oligarchs. Deserters soon began to stream in; the gravity of the situation was recognised by the Spartan government who landed more than four hundred of their best troops on the island of Sphacteria at the entrance to the bay. These were speedily isolated by the Athenian navy; and news of the event filled all Greece with excitement. A heated discussion took place at Athens, where Cleon accused Nicias, the commander-in-chief, of slackness in not capturing the blockaded force. Spartan overtures for a peace on condition of the return of the isolated men proved vain; after a lively altercation with Nicias Cleon made a promise to capture the Spartans within thirty days, a feat which he accomplished with the aid of Demosthenes. Nearly three hundred were found to prefer surrender to death; these were conveyed to Athens and were an invaluable asset for bargaining a future peace. A further success was the capture of Nisaea, the port of Megara, in 424, but an attempt to propagate democracy in Boeotia ended in a severe defeat at Delium; the fate of Plataea was a bad advertisement in an oligarchically governed district. Worse was to follow. Brasidas, a Spartan who had greatly distinguished himself at Pylos, passed through Thessaly with a volunteer force, reaching Thrace and capturing some important towns; the loss of one of these, Eion, caused the exile of the historian, who was too late to save it. In 423 a truce for one year was arranged between the combatants, but Brasidas ignored it, sowing disaffection among the Athenian allies. His personal charm gave them a good impression of the Spartan character and his offer of liberty was too attractive to be resisted. His success was partly due to a deliberate misrepresentation of the Athenian power which proved greater than it seemed to be. The two real obstacles to peace were Brasidas and Cleon; at Amphipolis they met in battle; a rash movement gave the Spartan an opportunity for an attack. He fell in action, but the town was saved. Cleon was killed in the same battle and the path to peace was clear. The truce for one year developed into a regular settlement in 421, Nicias being responsible for its negotiation in Athens. The chief clause provided that Athens should recover Amphipolis in exchange for the Spartan captives.