Here are links to an excellent four part series on Modern Paganism and the Ancient Mysteries at the Egregores blog.
I had not heard of Sallustius before, and his treatise sounds like it was written in this century almost. And I have not read Gardner’s Witchcraft Today in many years, so was happy to find a link in the article to download a PDF of it once again. Here is a quote from Part One:
“In Chapter XIII of The Meaning of Witchcraft, Gardner states (on page 170 of the 2004 Weiser edition), regarding ancient forms of Paganism and their relevance to Wicca, that “the only kinds of paganism with which we are concerned here are those which may have had some influence on the witch cult.” Gardner then names three such sources of influence in particular: (1) “Druidism, the religion of the Celts”, (2) “the religion of the Great Mother Goddess or the old Hunting God”, and (3) “the Mystery Cults of the ancient world”.
Having cited the Mystery Religions as an important part of Wicca’s connection with the ancient Pagan past, Gardner then poses the question, “have we any way of ascertaining what the Mysteries taught?” To which he immediately provides the answer:
“Fortunately, we have. In the fourth century A.D., when paganism was engaged in a fierce struggle with the new creed of Christianity, Sallustius, who was a close personal friend of the Emperor Julian (called the Apostate because he tried to restore the old religion), wrote a treatise called Peri Theon kai Kosmou, About the Gods and the World. It is probable that this treatise was a kind of manifesto of the highest type of paganism prevailing at that time, and it is evident that its author was an initiate of the Mysteries.”
I recommend a full reading of these articles which are very interesting indeed, especially Part 2 about the problem of evil, a thorny topic in any religion and philosophy. Enjoy.