In 430 BC, the army of Sparta looted Attica for a second time, but Pericles was not daunted and refused to revise his initial strategy. Unwilling to engage the Spartan army in battle, he again led a naval expedition to plunder the coasts of the Peloponnese, this time taking 100 Athenian ships with him. According to Plutarch, just before the sailing of the ships an eclipse of the sun frightened the crews, but Pericles used the astronomical knowledge he had acquired from Anaxagoras to calm them. In the summer of the same year an epidemic broke out and devastated the Athenians. The exact identity of the disease is uncertain; typhus or typhoid fever are suspected, but this has been the source of much debate. In any case, the city's plight, caused by the epidemic, triggered a new wave of public uproar, and Pericles was forced to defend himself in an emotional final speech, a rendition of which is presented by Thucydides. This is considered to be a monumental oration, revealing Pericles' virtues but also his bitterness towards his compatriots' ingratitude. Temporarily, he managed to tame the people's resentment and to ride out the storm, but his internal enemies' final bid to undermine him came off; they managed to deprive him of the generalship and to fine him at an amount estimated between 15 and 50 talents. Ancient sources mention Cleon, a rising and dynamic protagonist of the Athenian political scene during the war, as the public prosecutor in Pericles' trial.