Demosthenes, seeing that Nikias was thus obstinate, and conscious that his own project, when adopted, had led to a frightful disaster, ceased pressing him to raise the siege, and gave the other generals to understand that Nikias must have secret reasons, from his correspondents within the city, which led him to persevere thus obstinately in remaining where he was. This caused them also to withdraw their objections to remaining; but when another army came to assist the Syracusans, and the Athenians began to perish from malaria, even Nikias himself agreed that it was time to retreat, and issued orders to his men to hold themselves in readiness to embark. XXIII. When all was ready, and the enemy off their guard, as they did not expect the Athenians to retreat, an eclipse of the moon took place, which greatly terrified Nikias and some others who, from ignorance or superstition, were in the habit of taking account of such phenomena. That the sun should be sometimes eclipsed even the vulgar understood to be in some way due to the moon intercepting its light: but what body could intercept the moon's light, so that suddenly the full moon should pale its light and alter its colour, they could not explain, but thought that it was a sinister omen and portended some great calamity. The treatise of Anaxagoras, the first writer who has clearly and boldly explained the phases and eclipses of the moon, was then known only to a few, and had not the credit of antiquity, while even those who understood it were afraid to mention it to their most trusted friends. Men at that time could not endure natural philosophers and those whom they called in derision stargazers, but accused them of degrading the movements of the heavenly bodies by attributing them to necessary physical causes. They drove Protagoras into exile, and cast Anaxagoras into prison, from whence he was with difficulty rescued by Perikles; while Sokrates, who never took any part in these speculations, was nevertheless put to death because he was a philosopher. It was not until after the period of which I am writing that the glorious works of Plato shed their light upon mankind, proving that Nature obeys a higher and divine law, and removing the reproach of impiety which used to attach to those who study these matters, so that all men might thereafter investigate natural phenomena unreproved. Indeed, Plato's companion Dion, although the moon was eclipsed when he was starting from the island of Zakynthus to attack the despot Dionysius, was not in the least disturbed by the omen, but sailed to Syracuse and drove out the despot. Nikias at this time was without a competent soothsayer, for his intimate friend, Stilbides, who used to check a great deal of his superstition, died shortly before this. Indeed, the omen, if rightly explained, as Philochorus points out, is not a bad one but a very good one for men who are meditating a retreat; for what men are forced to do by fear,