The Merciful Knight, by Edward Burne-Jones [1893] (Public Domain Image)

Traces of a Hidden Tradition in Masonry and Medieval Mysticism by Isabel Cooper-Oakley [1900]

This is a set of essays by Isabel Cooper-Oakley, an early member of the Theosophists. She connects the dots between ancient wisdom schools and modern Freemasonry. At the root of this tree are a set of ideas from Hinduism, Zororastrianism, Gnosticism and early Christianity. Along the way she connects a number of links such as the Knights-Templars, the Troubadours and the Rosicrucians. She names dozens of even more obscure secret societies, heresies and conspiracies. The book finishes with an analysis of the Grail myth.

Cooper-Oakley writes from an openly Theosophical world-view. However, she is a more than competent historical writer, and quotes extensively from primary and secondary sources to make her point. This book provides abundant background information that anyone trying to understand this topic should have a grasp of.

The Heavenly Kingdom of the Holy Grail