The Greeks and Romans had various theories of the origin of things, all vague and admittedly conjectural. But the Christians, relying upon the inspired account in the Bible, built their theories on information which they believed vouchsafed to them by God himself. Their whole conception of human history was based upon a far more fundamental and thorough supernaturalism than we find among the Greeks and Romans. The pagan philosophers reckoned with the gods, to be sure, but they never assumed that man's earthly life should turn entirely on what was to happen after death. This was in theory the sole preoccupation of the mediaeval Christian. Life here below was but a brief, if decisive, preliminary to the real life to come. The mediaeval Christian was essentially more polytheistic than his pagan predecessors, for he pictured hierarchies of good and evil spirits who were ever aiding him to reach heaven or seducing him into the paths of sin and error. Miracles were of common occurrence and might be attributed either to God or the devil; the direct intervention of both good and evil spirits played a conspicuous part in the explanation of daily acts and motives.[20] As a distinguished church historian has said, the God of the Middle Ages was a God of arbitrariness--the more arbitrary the more Godlike. By frequent interferences with the regular course of events he made his existence clear, reassured his children of his continued solicitude, and frustrated the plots of the Evil One. Not until the eighteenth century did any considerable number of thinkers revolt against this conception of the Deity and come to worship a God of orderliness who abode by his own laws. The mediaeval thinkers all accepted without question what Santayana has strikingly described as the "Christian Epic". This included the general historical conceptions of how man came about, and how, in view of his origin and his past, he should conduct his life. The universe had come into being in less than a week, and man had originally been created in a state of perfection along with all other things--sun, moon, and stars, plants and animals. After a time the first human pair had yielded to temptation, transgressed God's commands, and been driven from the lovely garden in which he had placed them. So sin came into the world, and the offspring of the guilty pair were thereby contaminated and defiled from the womb.