ABSTRACT
It was in the course of the tenth and eleventh centuries of our era (fourth and fifth centuries after the Hegira) that the Ismaili theosophy took form in great systematic works, chiefly under the influence of several great Iranian thinkers.! One of these thinkers, Abu I;Iatim Razi, whose work, like so many others, still exists only in manuscript, was a Fatimid dignitary (da'i) in the Dailam (region to the southwest of the Caspian Sea). He was a contemporary of the celebrated l\lobammad ibn Zakariya Razi (the Rhazes of the Latin writers of the Middle Ages, d. ca. 923-32), a physician and alchemist suspected of crypto-Manichaeism, whose philosophical work has today been in large part lost.2 As their name indicates, both men have a bond with Rhages (the city mentioned in the book of Tobit, the Ragha of the Avesta, today Rayy, several kilometers south of Teheran). It is fortunate for philosophy that these two eminent contemporaries should have met and known each other and that, moreover, since Zakariya Razi was (even posthumously) the object of Ismaili attacks,3 these two fine minds should have clashed in controversies which were no less intense for all their courtesy.
