The earlier centuries of our era were for the Græco-Roman world a period not merely of a general feeling of unrest, consequent upon the collapse of the older religions, and the social changes resulting from a long series of revolutions, but also of vigorous attempts at reconstruction, in which both the ends aimed at, and the methods adopted for their attainment--preaching, teaching, asceticism, mystic symbolism, etc.--were closely akin to those of the Christian propaganda; indeed, it was no uncommon thing for a seeker in religion, drifting about from one sect or cult to another, to take Christianity in his way, thus keeping open an additional channel by which Pagan and Christian ideas were brought to bear upon one another. Throughout all these ages speculations were rife, for which was claimed the authority of Orpheus, Pythagoras, Empedocles, Heraclitus, or some other of the ancient mystics or philosophers, and all of these, conjoined with the similar beliefs held by the later Stoics in many varying forms, tended to foster the Church’s expectation of the approaching end of the world. This theory derived further support from the great authority ascribed to the so-called Sibylline books, a long series of forgeries extending, probably, from the end of the second century B.C. to the fourth century of our era, if not later, containing a chaotic mass of prophecies and oracles, to which Judaism, Christianity, and Hellenic mysticism had all added their quota, and in which the proximate destruction of the world by fire, and the renewal of things, is a constantly recurring idea. Another of the many causes which kept men’s minds directed towards the Otherworld was the legend, current in the Church from the earliest times, and surviving far into the Middle Ages,[86] of the ‘Harrowing of Hell’ by Our Lord in the interval between the Burial and the Resurrection. One of the earliest versions of this legend occurs in Part II. of the so-called _Gospel of Nicodemus_, Greek text, which relates how He ‘raised many of the dead, who appeared unto many in Jerusalem,’ and then described Christ’s descent into Hades, which had been preceded by a visit of St. John Baptist, who came to the Old Testament prophets, among whom Enoch and Elijah are especially mentioned, and expounded to them the Christian Revelation. From the contemplation of the end of the world to speculation concerning the world to come, and the state of the departed spirits there, was but a step. Accordingly, as is but natural, many of the teeming crop of apocryphal Gospels, Acts, and Revelations which sprang up during the earlier ages of the Church are composed with a distinctly eschatological purpose.