The main difference in the social function of chastity as we pass from savagery to higher stages of culture seems to be that it ceases to exist as a general hygienic measure or a general ceremonial observance, and, for the most part, becomes confined to special philosophic or religious sects which cultivate it to an extreme degree in a more or less professional way. This state of things is well illustrated by the Roman Empire during the early centuries of the Christian era.[73] Christianity itself was at first one of these sects enamored of the ideal of chastity; but by its superior vitality it replaced all the others and finally imposed its ideals, though by no means its primitive practices, on European society generally. Chastity manifested itself in primitive Christianity in two different though not necessarily opposed ways. On the one hand it took a stern and practical form in vigorous men and women who, after being brought up in a society permitting a high degree of sexual indulgence, suddenly found themselves convinced of the sin of such indulgence. The battle with the society they had been born into, and with their own old impulses and habits, became so severe that they often found themselves compelled to retire from the world altogether. Thus it was that the parched solitudes of Egypt were peopled with hermits largely occupied with the problem of subduing their own flesh. Their pre-occupation, and indeed the pre-occupation of much early Christian literature, with sexual matters, may be said to be vastly greater than was the case with the pagan society they had left. Paganism accepted sexual indulgence and was then able to dismiss it, so that in classic literature we find very little insistence on sexual details except in writers like Martial, Juvenal and Petronius who introduce them mainly for satirical ends. But the Christians could not thus escape from the obsession of sex; it was ever with them. We catch interesting glimpses of their struggles, for the most part barren struggles, in the Epistles of St. Jerome, who had himself been an athlete in these ascetic contests.