Now, doctrines such as these were not only very prevalent during the Middle Ages, when alchemy so greatly flourished, but are of great antiquity, and were undoubtedly believed in by the learned class in Egypt and elsewhere in the East in those remote days when, as some think, alchemy originated, though the evidence, as will, I hope, become plain as we proceed, points to a later and post-Christian origin for the central theorem of alchemy. So far as we can judge from their writings, the more important alchemists were convinced of the truth of these doctrines, and it was with such beliefs in mind that they commenced their investigations of physical and chemical phenomena. Indeed, if we may judge by the esteem in which the Hermetic maxim, "What is above is as that which is below, what is below is as that which is above, to accomplish the miracles of the One Thing," was held by every alchemist, we are justified in asserting that the mystical theory of the spiritual significance of Nature--a theory with which, as we have seen, is closely connected the Neoplatonic and Kabalistic doctrine that all things emanate in series from the Divine Source of all Being--was at the very heart of alchemy. As writes one alchemist: "... the Sages have been taught of God that this natural world is only an image and material copy of a heavenly and spiritual pattern; that the very existence of this world is based upon the reality of its celestial archetype; and that God has created it in imitation of the spiritual and invisible universe, in order that men might be the better enabled to comprehend His heavenly teaching, and the wonders of His absolute and ineffable power and wisdom. Thus the sage sees heaven reflected in Nature as in a mirror; and he pursues this Art, not for the sake of gold or silver, but for the love of the knowledge which it reveals; he jealously conceals it from the sinner and the scornful, lest the mysteries of heaven should be laid bare to the vulgar gaze."(1) (1) MICHAEL SENDIVOGIUS (?): _The New Chemical Light, Pt. II., Concerning Sulphur_. (See _The Hermetic Museum_, vol. ii. p. 138.)