Although the leading tenets of Demonology may be traced to the Jews and early Christians, yet they were matured by our early communications with the Moors of Spain, who were the chief philosophers of the dark ages, and between whom and the natives of France and Italy, a great communication existed. Toledo, Seville and Salamanca, became the greatest schools of magic. At the latter city predilections on the black art from a consistent regard to the solemnity of the subject were delivered within the walls of a vast and gloomy cavern. The schoolmen taught that all knowledge might be obtained from the assistance of the fallen angels. They were skilled in the abstract sciences, in the knowledge of precious stones, in alchymy, in the various languages of mankind and of the lower animals; in the Belles-Lettres, Moral Philosophy, Pneumatology, Divinity, Magic, History, and Prophecy. They could controul the winds and waters, and the stellar influences. They could cause earthquakes, induce diseases or cure them, accomplish all vast mechanical undertakings, and release souls out of Purgatory. They could influence the passions of the mind, procure the reconciliation of friends or of foes, engender mutual discord, induce mania, melancholy, or direct the force and objects of human affection. Such was the Demonology taught by its orthodox professors. Yet other systems of it were devised, which had their origin in the causes attending the propagation of christianity; for it must have been a work of much time to eradicate the almost universal belief in the pagan deities, which had become so numerous as to fill every creek and corner of the universe with fabulous beings. Many learned men, indeed, were induced to side with the popular opinion on the subject, and did nothing more than endeavour to unite it with their acknowledged systems of Demonology. They taught that the objects of heathen reverence were fallen angels in league with the Prince of Darkness, who, until the appearance of our Saviour, had been allowed to range on the earth uncontrolled, and to involve the world in spiritual darkness and delusion.