the Ishma'ilians on the part of those who wished to return to the original aims of the movement.
The published work of the brotherhood appears in a series of 51 epistles, the Rasa'il ikhwani s-Safa, which form an encyclopædia of philosophy and science as known to the Arabic-speaking world in the 4th cent. A.H. They do not propose any new theories but simply furnish a manual of current material. The whole text of these epistles has been printed at Calcutta, whilst portions of the voluminous whole have been edited by Prof. Dieterici between 1858 and 1872, and these were followed in 1876 and 1879 by two volumes called Makrokosmos and Mikrokosmos, in which an epitome is presented of the whole work. It appears that the leading spirit in the preparation of this encyclopædia was Zayd b. Rifa'a, and with him were associated Abu Sulayman Muhammad al-Busti, Abu l-Hasan 'Ali az-Zanjani, Abu Ahmad al-Mahrajani, and al-Awfi, but it does not follow that these were the founders of the brotherhood, as some have supposed.
A great part of the Epistles of the Brotherhood deals with logic and the natural sciences, but when the writers turn to metaphysics, psychology, or theology, we find very clear traces of the neo-Platonic doctrines as contained in Alexander of Aphrodisias and matured by Plotinus. God, we read, is above all knowledge and above all the categories of human thought. From God proceeds the 'aql or intelligence, a complete spiritual emanation which contains in itself the forms
