The papyrus is of the Ptolemaic period, but the exact date is uncertain, as the colophon at the end is partly illegible. The year 15 only is visible, which, however, is not sufficient guide to the reign of the king under whom it was written.
The legend given in this book is part only of a much longer tale; it is in fact a story within a story, told by the ka of Ahura to the high priest of Memphis, when he ventured into the tomb of Nefer-ka-ptah in search of the Book of Thoth.
The Book of Thoth is said to contain only two pages; it must therefore have been a roll of papyrus written on both sides.
Original: Plutarch, De Iside et Osiride.
Translated: Mead, Thrice-greatest Hermes, i, 278.
The treatise on Isis and Osiris was written by Plutarch, himself an initiate into the Osiris-mysteries, to a fellow-initiate, a woman named Klea. It was written at Delphi in the second century A.D.
It is the only connected account remaining of the death of Osiris and the wanderings of Isis. Though of so late a date, it is found to be correct on the whole when checked by the inscriptions and sculpture of Pharaonic times.
The so-called Ritual of Denderah is our principal authority for the worship of Osiris in the chief temples of Egypt on the festivals of the month of Khoiakh. The Ritual is sculptured on the walls of the temple of Denderah, and gives in great detail the rites in use, and even the size and material of the symbolical images. The inscription dates to the Ptolemaic period, but the Ritual is considerably earlier.
"Mystery-plays" of the death of Osiris and of the repulse of Set by Horus appear to have been enacted on certain great occasions at the chief centres of worship. The principal part was that of Horus, which was acted by the Pharaoh himself in the capital, and by the chief local notabilities in provincial centres.