Mystery schools of ancient Egypt, Greece, Babylonia, and India

There's has been much talk--probably since the advent of Harry Potter--about "mystery schools" in the ancient world, and even to the present. Mainstream academics seem to avoid the subject. Freemasonry, Rosicrucianism, Hermeticism, and Kabbalah--just to name a few--seem to have hoarded ancient knowledge over the many centuries of religious zeal. I believe that to be true, and justified... but often self-serving.

Sometimes the Druids are included within the mystery schools of ancient times, but somehow a shared-knowledge network stretching from Ireland to India thousands of years ago seem a bit far-fetched to me. I do think that ancient peoples had knowledge of how to use the Earth's energy in areas of anti-gravity, alchemy, sacred geometry, etc.

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