the West for the priests, and became so numerous that it could be ranked as a tribe among the other tribes of the Medes. The formation of this order was already complete when, after the middle of the seventh century B.C., the Medes rebelled against the kings of Asshur. Meanwhile the Athravas of the East were busily occupied in developing and fixing the contents and meaning of the new idea of God, and of the ethics resulting from it. They ranged the old gods under the new doctrine, and determined their relation to the new supreme deity; they peopled heaven with shapes corresponding to the reformed teaching, and brought mythology into harmony with it; from the commands of purity they developed in the spirit of the reformed religion the rules of purification and the removal of impurities as required in every occurrence of life. Thus, beside the old invocations of the gods, arose theories of a speculative cast which sought to regard the gods as ethical forces, and prayers of a formal character; from the dialectic of the priestly schools was developed a very complicated system of purity of life, of rubrics for expiation and purification, in which formalism and casuistry were not wanting. Enquiries arose how law and justice should be shaped so as to conform to the rules of religion; while, on the other hand, the old sacrificial songs were collected, the liturgy was fixed, as well as the order of the festivals and sacrifices for the new moon and full moon, and the course of the year; the prescriptions of medicine were written down, and those cycles formed which comprised the battle between Auramazda and Angromainyu down to the last and eternal victory of light and life. After various attempts at compilation, the priests of the East finally succeeded in uniting the sum of these labours into one great whole, which was the canon of the sacred scriptures. We may assume that the labours of the priesthood of Bactria, which came to an end with this result, may have occupied the same space of time as the growth and writing down of the Brahmanas on the Ganges. There are good reasons for supposing that the canon was finally established about the year 600 B.C., and therefore, on the calculation given, the labours of the priests upon it must have commenced about the year 800 B.C.