In Europe, during the period of classic antiquity, hydromancy was especially practised. The Byzantine Andronicus Comnenus also put his faith concerning the knowledge of future things, in water. Christianity denounced the practice of these magic arts as the work of the devil. St. Thomas Aquinas says that the gift of seeing visions possessed by children, is not to be ascribed to any power of innocence but to evil influences. Despite this however the art did not perish. Indeed, in the sixteenth century, under the protection of physicians and University professors, it attained the acme of its development. The celebrated humanist Pico de Mirandola was firmly convinced of the power of magic mirrors, and declared that it was sufficient in order to read in a magic mirror the past, the present, and the future, simply to construct one under a favorable constellation and at the proper temperature. But the most successful of all in the practice of crystallomancy was Dr. Dee, who flourished from 1527 to 1608. His seer or scryer was a man named Kelly, who could hardly be described as "unpolluted" or as "one that had not known sin," for he had been the perpetrator of so many villainies that as a testimony of his character both his ears had been cut off. A crystal served as the vehicle of the ecstatic revelations, to which according to the conception of the times numerous spirits were attached, who made themselves intelligible to Kelly by dramatic scenes and often by sounds. The Shew-Stone, or Holy Stone, was round and rather large; it is said to have come into Dee's hands in a very wonderful manner. The large folio volume of the English mathematician upon crystallomancy was very probably used later by Cagliostro, although the latter practised a somewhat different method and used a carafe of water instead of the stone. The prophecy of the magician who predicted the regency of the Duke of Orleans through the death of the Prince, is to be noticed as the last historical case of the use of the magic mirror.