In the Shia façon, the belief in the Mahdi is essential, being, in the hearts of the multitude as well as in the declarations of the theologians, identified with the return of the Hidden Imam. The history of the Imams is a long one, since it is thought to begin with the existence of God's primordial Word and Spirit in a cosmic epoch before time and creation. From this pleromatic state, and into the world of time and man, a chain of successors was established by God. As such, they were all equipped with a special kind of knowledge and certain spiritual qualities in order to guide and lead the believers right, and moreover, provide for the intellectual and religious needs of man. In accordance with this view, it was held that the Prophet Muhammad had communicated his esoteric knowledge to Ali, who in his turn, had handed it over to his own sons. Thus, among the Kaysanis there was the view that Muhammad b. Hanafiya, a son of Ali by another spouse than Fatima, was held to be the master of all the sciences, and all the mysteries connected with the interpretation of the Koran, the sciences of the remote regions and psychology, which he had acquired from Ali and Husayn, the two Sayyids preceding him. In a more elaborate version, this idea of possessing and conveying such insight was said to be founded on the following dual concept of reality: “There is an esoteric side to everything external, a spirit to every form, a hidden meaning, ta’wil, to every revelation, and to every similitude in this world a corresponding reality in the other world”.