After the death of Pericles, the Athenians turned somewhat against his conservative, defensive strategy and to the more aggressive strategy of bringing the war to Sparta and its allies. Rising to particular importance in Athenian democracy at this time was Cleon, a leader of the hawkish elements of the Athenian democracy. Led militarily by a clever new general Demosthenes (not to be confused with the later Athenian orator Demosthenes), the Athenians managed some successes as they continued their naval raids on the Peloponnese. Athens stretched their military activities into Boeotia and Aetolia, quelled the Mytilenean revolt and began fortifying posts around the Peloponnese. One of these posts was near Pylos on a tiny island called Sphacteria, where the course of the first war turned in Athens's favor. The post off Pylos struck Sparta where it was weakest: its dependence on the helots, who tended the fields while its citizens trained to become soldiers. The helots made the Spartan system possible, but now the post off Pylos began attracting helot runaways. In addition, the fear of a general revolt of helots emboldened by the nearby Athenian presence drove the Spartans to action. Demosthenes, however, outmaneuvered the Spartans in the Battle of Pylos in 425 BC and trapped a group of Spartan soldiers on Sphacteria as he waited for them to surrender. Weeks later, though, Demosthenes proved unable to finish off the Spartans. After boasting that he could put an end to the affair in the Assembly, the inexperienced Cleon won a great victory at the Battle of Sphacteria. In a shocking turn of events, 300 Spartan hoplites encircled by Athenian forces surrendered. The Spartan image of invincibility took significant damage. The Athenians jailed Sphacterian hostages in Athens and resolved to execute the captured Spartans if a Peloponnesian army invades Attica again.