teachers” (rabbotai), and this expression, by which he merely describes his indebtedness to their writings, has been taken in its literal meaning. Whoever his teachers may have been, it is evident that he was well prepared by them for his future mission. At the age of twenty-three he entered upon his literary career with a treatise on the Jewish Calendar. It is unknown where this work was composed, whether in Spain or in Africa. The author merely states that he wrote it at the request of a friend, whom he, however, leaves unnamed. The subject was generally considered to be very abstruse, and to involve a thorough knowledge of mathematics. Maimonides must, therefore, even at this early period, have been regarded as a profound scholar by those who knew him. The treatise is of an elementary character.—It was probably about the same time that he wrote, in Arabic, an explanation of Logical terms, Millot higgayon, which Moses Ibn Tibbon translated into Hebrew. The earlier period of his life does not seem to have been marked by any incident worth noticing. It may, however, be easily conceived that the later period of his life, which was replete with interesting incidents, engaged the exclusive attention of his biographers. So much is certain, that his youth was beset with trouble and anxiety; the peaceful development of science and philosophy was disturbed by wars raging between Mohammedans and Christians, and also between the several Mohammedan sects. The Moravides, who had succeeded the Omeyades, were opposed to liberality and toleration; but they were surpassed in cruelty and fanaticism by their successors. Cordova was taken by the Almohades in the year 1148, when Maimonides was about thirteen years old. The victories of the Almohades, first under the leadership of the Mahadi Ibn Tamurt, and then under Abd-al-mumen, were, according to all testimonies, attended by acts of excessive intolerance. Abd-al-mumen would not suffer in his dominions any other faith but the one which he himself confessed. Jews and Christians had the choice between Islam and emigration or a martyr’s death. The Sefer ha-ḳabbalah contains the following description of one of the persecutions which then occurred: