The discrimination, however, made in the treatment of the theoretical and practical denial of the gods is certainly not due merely to consideration of the more or less isolated occurrence of the phenomenon; it is rooted at the same time in the very nature of ancient religion. The essence of ancient polytheism is the worship of the gods, that is, cultus; of a doctrine of divinity properly speaking, of theology, there were only slight rudiments, and there was no idea of any elaborate dogmatic system. Quite different attitudes were accordingly assumed towards the philosopher, who held his own opinions of the gods, but took part in the public worship like anybody else; and towards the monotheist, to whom the whole of the Pagan worship was an abomination, which one should abstain from at any cost, and which one should prevail on others to give up for the sake of their own good in this life or the next. In the literature of antiquity we meet with sporadic statements to the effect that certain philosophers bore the epithet _atheos_ as a sort of surname; and in a few of the later authors of antiquity we even find lists of men—almost all of them philosophers—who denied the existence of the gods. Furthermore, we possess information about certain persons—these also, if Jews and Christians are excluded, are nearly all of them philosophers—having been accused of, and eventually convicted of, denial of the gods; some of these are not in our lists. Information of this kind will, as remarked above, be taken as the point of departure for an investigation of atheism in antiquity. For practical reasons, however, it is reasonable to include some philosophers whom antiquity did not designate as atheists, and who did not come into conflict with official religion, but of whom it has been maintained in later times that they did not believe in the existence of the gods of popular belief. Thus we arrive at the following list, in which those who were denoted as _atheoi_ are italicised and those who were accused of impiety are marked with an asterisk: Xenophanes. *Anaxagoras. _ Diogenes of Apollonia._ _ Hippo of Rhegium._ *_Protagoras._ _ Prodicus._ _ Critias._ *_Diagoras of Melos._ *Socrates. Antisthenes. Plato. *Aristotle. Theophrastus. *Stilpo. *_Theodorus._ *_Bion._ _ Epicurus._ _ Euhemerus._