It is infinitely probable that this doctrine of reincarnation in the bodies of animals was in Greece a foreign importation. Herodotus thought that it came from Egypt,[439] but it does not seem to have existed in that country in ancient times in the form of a regular succession of transmigrations. On the other hand, Greek metempsychosis shows a resemblance, striking even in details, to one of the fundamental conceptions of the religious thought of India, that of _samsâra_, which was accepted as a dogma there long before the birth of Buddhism. The most probable opinion is that this idea made its way across the Persian Empire and thus reached the Orphics and Pythagoreans. It is, however, not unlikely that, like Babylonian astrology, Hindu eschatology was propagated as far as Egypt at a comparatively recent date, that is, about the sixth century B. C., and that the information given by the father of history may be at least partly correct, Egypt having served as an intermediary between India and Greece. We have not, however, to discuss here this problem of the origins of metempsychosis, nor to follow the development of the doctrine in ancient Greek philosophy. In the period with which we are concerned, it had already long been traditional in the Pythagorean and Platonic schools, it was not only a philosophical theory but also a tenet admitted by several religions. We can leave unanswered the questions of whether, as the ancients affirm, the Druids believed in it, being in this particular disciples of Pythagoras, and of whether the Etruscans were persuaded to it by the teaching of the philosopher of Croton. It is, however, certain that transmigration was in the East an article of widely held belief. We find it accepted by the mysteries of Mithras and by Manicheism, and it survives to our own day in Syria among the sects of the Druses,[440] the Yezidis and the Nosaïris.[441] What was its form in the Roman period, and how was it brought into harmony with traditional or acquired ideas as to the future life?