It has also been common to frame statements of the moral philosophy which dominated in those centuries, entirely from the data afforded by earlier writers, and to account for the existence of nobler elements in contemporary writers by the hypothesis that Seneca, Epictetus, and Marcus Aurelius, had come into contact with Christian teachers. In the case of Seneca, the belief in such contact went so far as to induce a writer in an imitative age to produce a series of letters which are still commonly printed at the end of his works, and which purport to be a correspondence between him and St. Paul. It is difficult, no doubt, to prove the negative proposition that such writers did not come into contact with Christianity; but a strong presumption against the idea that such contact, if it existed, influenced to any considerable extent their ethical principles, is established by the demonstrable fact that those principles form an integral part of their whole philosophical system, and that their system is in close logical and historical connection with that of their philosophical predecessors.[231] * * * * * It will be found on a closer examination that the age in which Christianity grew was in reality an age of moral reformation. There was the growth of a higher religious morality, which believed that God was pleased by moral action rather than by sacrifice.[232] There was the growth of a belief that life requires amendment.[233] There was a reaction in the popular mind against the vices of the great centres of population. This is especially seen in the large multiplication of religious guilds, in which purity of life was a condition of membership: it prepared the minds of men to receive Christian teaching, and forms not the least important among the causes which led to the rapid dissemination of that teaching: it affected the development of Christianity in that the members of the religious guilds who did so accept Christian teaching, brought over with them into the Christian communities many of the practices of their guilds and of the conceptions which lay beneath them. The philosophical phase of the reformation began on the confines of Stoicism and Cynicism. For Cynicism had revived. It had almost faded into insignificance after Zeno and Chrysippus had formed its nobler elements into a new system, and left only its “dog-bark”[234] and its squalor. But when the philosophical descendants of Zeno and Chrysippus had become fashionable _littérateurs_, and had sunk independence of thought and practice in a respectability and “worldly conformity” which the more earnest men felt to be intolerable, Cynicism revived, or rather the earlier and better Stoicism revived, to re-assert the paramount importance of moral conduct, and to protest against the unnatural alliance between philosophy and the fashionable world.