Towards the end of the old world, the Greek theory of human nature yielded to a very different conception. The opposition between the opinions of the Stoics on morality, and their admiration of human nature, led Seneca, one of the last Roman Stoics and a celebrated contemporary of Jesus Christ, to break completely away from the ancient doctrine. Convinced of the moral weakness and imperfection of man, and of the persisting power of evil, Seneca declared that human nature contained a vicious and essentially evil element. This element was seated in the body, which he regarded as so essentially vile that it is to be despised. Our body was no more than the dwelling of the soul, its temporary home, a place in which it cannot be at rest. The body was a burden which the soul would be rid of, a prison-house from which it would escape. According to Seneca[19] the soul must wrestle with the body, for the body brings to it nothing but suffering, while the soul is essentially pure and spotless, and as much above the body as divinity is above matter. A dualism still more pronounced was characteristic of the early Christian view of human nature, and led to the depreciation of the body as compared with the soul. In the fourth and fifth centuries of our era such a view was so dominant that a struggle against the material side of our nature became a rule of life. The most absolute asceticism spread throughout the Christian world.[20] A struggle against hunger, thirst, and desire for sleep, rejection of all pleasures that come from impressions of sight, of hearing, or of the palate, and, above all, abstention from sexual intercourse, became, in the opinion of believers, the true aim of human life. The conviction that human nature was essentially corrupt led to a declaration of war against it; all the pleasures were forbidden, even the most innocent of them being thought vicious. What could be more in contrast with the calm and joyous philosophy of the Greeks, for whom there did not exist the idea of a struggle against the supposed corruption and imperfection of man? The dualistic theory made such demands on its proselytes that these, absorbed in the salvation of their souls, sank from the physical point of view to the level of wild beasts. Hermits resorted to the lairs of animals, abandoned their clothing and went about naked with shaggy and disordered hair. In Mesopotamia and a part of Syria there arose a sect of eaters of grass; these were people who had no dwellings and who ate neither bread nor vegetables, but wandered on the hills and fed on the herbage. Cleanliness of the body was regarded as an indication of corruptness of the soul, and among the most highly venerated of the saints were those who took no care of the body. Athanasius relates with approval that when St. Antony, the father of monks, became old he never washed his feet.[21]