Could that be our year zero?
The Joy of Satan is the revival and continuation of the lost Spiritual sects under the Gods, there have been many like us, from the recent Thule society and SS in NS Germany, to the Free Masons, the Greek Philosophers, the Founding Fathers of America, the Egyptian Brotherhood of the Snake, the other ancient temples from the lost civilizations, there have been countless many throughout the ages, some were individuals who had personal relations with the Gods and did not have a community due to the difficulties of the Era, while others had strong communities which lasted for hundreds of years or longer.
We are direct successors and the ones to carry on the torch into the next era as the Temple of the Gods. The above are only examples from our Earth, on which our history is at least 72.000 years long, however Spiritual Satanism extends beyond the Earth, and has existed for an extraordinarily long time, flourishing through different worlds and even different dimensions.
Thus, the year 0 for Spiritual Satanism is the very first onset of Spiritual Satanism in any realm. Satan is our root, as what we follow stems from Him, and He has always been there.
Our beliefs are older than history itself, perhaps older than the universe.