It now remains for us to describe the development of the Kabbalah, to point out the different schools into which its followers are divided, and to detail the literature which this theosophy called into existence in the course of time. The limits of this Essay demand that this should be done as briefly as possible. The great land mark in the development of the Kabbalah is the birth of the Sohar, which divides the history of this theosophy into two periods, viz., the pre-Sohar period and the post-Sohar period. During these two periods different schools developed themselves, which are classified by the erudite historian, Dr. Graetz, as follows:— [82] I.—THE SCHOOL OF GERONA, so called from the fact that the founders of it were born in this place and established the school in it. To this school, which is the cradle of the Kabbalah, belong 1. Isaac the Blind (flour. 1190–1210), denominated the Father of the Kabbalah. His productions have become a prey to time, and only a few fragments have survived as quotations in other theosophic works. From these we learn that he espoused the despised doctrine of metempsychosis as an article of creed, and that from looking into a man’s face, he could tell whether the individual possessed a new soul from the celestial world of spirits, or whether he had an old soul which has been migrating from body to body and has still to accomplish its purity before its return to rest in its heavenly home. 2. Azariel and Ezra, disciples of Isaac the Blind. The former of these is the author of the celebrated Commentary on the Ten Sephiroth, which is the first Kabbalistic production, and of which we have given an analysis in the second part of this Essay (vide supra, p. 176). Of Ezra next to nothing is known beyond the fact that his great intimacy with Azariel led some writers to identify the two names. 3. Jehudah b. Jakar, a contemporary of the foregoing Kabbalists. No works of his have survived, and he is only known as the teacher of the celebrated Nachmanides and from being quoted as a Kabbalistic authority.