To the discerning few it is evident that Mohammed had a knowledge of that secret doctrine which must needs constitute the core of every great philosophical, religious, or ethical institution. Through one of four possible avenues Mohammed may have contacted the ancient Mystery teachings: (1) through direct contact with the Great School in the invisible world; (2) through the Nestorian Christian monks; (3) through the mysterious holy man who appeared and disappeared at frequent intervals during the period in which the suras of the Koran were revealed; (4) through a decadent school already existing in Arabia, which school in spite of its lapse into idolatry still retained the secrets of the Ancient Wisdom cult. The arcana of Islam may yet be demonstrated to have been directly founded upon the ancient pagan Mysteries performed at the Caaba centuries before the birth of the Prophet; in fact it is generally admitted that many of the ceremonials now embodied in the Islamic Mysteries are survivals of pagan Arabia.