А с современной точки зрения - все атеисты, потому что в Зевса не верят.
Atheism In Pagan Antiquity By A. B. Drachmann
A difficulty that occurred at the very beginning of the inquiry was how to define the notion of atheism. Nowadays the term is taken to designate the attitude which denies every idea of God.
Even antiquity sometimes referred to atheism in this sense; but an inquiry dealing with the history of religion could not start from a definition of that kind. It would have to keep in view, not the philosophical notion of God, but the conceptions of the gods as they appear in the religion of antiquity. Hence I came to define atheism in Pagan antiquity as the point of view which denies the existence of the ancient gods.
In the sense in which the word is used here we are nowadays all of us atheists. We do not believe that the gods whom the Greeks and the Romans worshipped and believed in exist or have ever existed; we hold them to be productions of the human imagination to which nothing real corresponds. This view has nowadays become so ingrained in us and appears so self-evident
It might seem more natural, in dealing with atheism in antiquity, to adopt the definition current among the ancients themselves. That this method would prove futile the following investigation will, I hope, make sufficiently evident; antiquity succeeded as little as we moderns in connecting any clear and unequivocal idea with the words that signify “denial of God.”
On the other hand, it is, of course, impossible to begin at all except from the traditions of antiquity about denial and deniers.
Hence the course of the inquiry will be, first to make clear what antiquity understood by denial of the gods and what persons it designated as deniers, and then to examine in how far these persons were atheists in our sense of the word.
Seen from this point of view, our brief sketch of the attitude of posterity towards the religion of the pagan world will also not be without interest. If, after isolated advances during the mighty awakening of the Renaissance, it is not until the transition from the seventeenth to the eighteenth century that we find the modern atheistic conception of the nature of the gods of the ancients established in principle and consistently applied, we can scarcely avoid connecting this fact with the advance of natural science in the seventeenth century, and not least with the victory of the heliocentric system. After the close of antiquity the pagan gods had receded to a distance, practically speaking, because they were not worshipped any more. No one troubled himself about them. But in theory one had got no further, i.e. no advance had been made on the ancients, and no advance could be made as long as supernaturalism was adhered to in connexion with the ancient view of the universe. Through monotheism the notions of the divinity of the sun, moon and planets had certainly been got rid of, but not so the notion of the world—i.e. the globe enclosed within the firmament—as filled with personal beings of a higher order than man; and even the duty of turning the spheres to which the heavenly bodies were believed to be fastened was—quite consistently—assigned to some of these beings. As long as such notions were in operation, not only were there no grounds for denying the reality of the pagan gods, but there was every reason to assume it. So far we may rightly say that it was Copernicus, Galileo, Giordano Bruno, Kepler and Newton that did away with the traditional conception of ancient paganism.
Natural science, however, furnishes only the negative result that the gods of polytheism are not what they are said to be:
real beings of a higher order than man. To reveal what they are, other knowledge is required. This was not attained until long after the revival of natural science in the sixteenth and  seventeenth centuries. The vacillation in the eighteenth century between various theories of the explanation of the nature of ancient polytheism—theories which were all false, though not equally false—is in this respect significant enough; likewise the gradual progress which characterises research in the nineteenth century, and which may be indicated by such names as Heyne, Buttmann,K.O.Müller,Lobeck,Mannhardt,Rohde,andUsener, to mention only some of the most important and omitting those still alive. Viewed in this light the development sketched here within a narrowly restricted field is typical of the course of European intellectual history from antiquity down to our day.