Perhaps no subject has gained so much from the application of the new historical method as that which we have now to study in its connexion with the progress of Greek philosophy. This is the religion of the Roman empire. On former occasions, we have had to observe how fruitful was the interaction between faith and reason in the early stages of Greek thought. We have now to show how the same process was continued on a greater scale during its later development and diffusion. The conditions and results of this conflict have sometimes been gravely misconceived. We have said that in more than one direction important advances were made under the empire. In the direction of pure rationalism, however, there was no advance at all, but, on the contrary, a continual loss of the ground formerly won. The polytheism which Christianity displaced turns out to have been far more vigorous and fertile than was once supposed, and in particular to have been supported by a much stronger body not only of popular sentiment, but, what at first seems very surprising, of educated conviction. We were formerly taught to believe that the faith of Homer and Aeschylus, of Pythagoras and Pheidias, was in the last stage of decrepitude when its destined successor appeared, that it had long been abandoned by the philosophers, and was giving place in the minds of the vulgar to more exciting forms of superstition newly imported from the East. The undue preponderance given to purely literary sources of information is largely responsible for an opinion which now appears to have been mistaken. Among the great Roman writers, Lucretius proclaims himself a mortal enemy to religion; Ennius and Horace are disbelievers in providence; the attitude of Juvenal towards the gods and towards a future life is at least ambiguous, and that of Tacitus undecided; Cicero attacks the current superstitions with a vigour which has diverted attention from the essentially religious character of his convictions; Lucian, by far the most popular Greek writer of the empire, is notorious for his hostility to every form of theology. Among less known authors, the elder Pliny passionately denounces the belief in a divine guidance of life and in the immortality of the soul.[306] Taken alone, these instances would tend to prove that sceptical ideas were very widely diffused through Roman society, both before and after the establishment of the empire. Side by side, however, with the authorities just cited there are others breathing a very different spirit; and what we have especially to notice is that with the progress of time the latter party are continually gaining in weight and numbers. And this, as we shall now proceed to show, is precisely what might have been expected from the altered circumstances which ensued when the civilised world was subjected to a single city, and that city herself to a single chief. II.