In this book first published in 1900, Isabel Cooper Oakley has gathered together extensive source material in presenting this history of mysticism in Medieval Europe. The survey covers some eighteen hundred years, and shows with documented evidence a definite link between the seemingly divergent occult schools and brotherhoods that flourished, and that the source of their knowledge lay in Ancient India, the home of Brahma Vidya or esoteric science. Gradually over the years visiting seers and teachers brought this wisdom to Egypt, Persia and Greece, which was given expression in the great mystery schools and temples. A vast tapestry of the spiritual life is unfolded before us, the Gnostic sects who founded Christianity, the famous occult schools of Averroes and the Arabian mystics in Toledo, the Alchemists and Rosicrucians, and the Grail Legend, preserved in times of religious persecution by the troubadours whose allegorical songs were a feature of the royal courts, and the Knights Templars who designed and built the Gothic cathedrals.