The philosopher, Chasdaï Crescas, also came forward in gallant defense of the religion of his fathers. He composed (1396) a polemical treatise (Tratado), in which he tested philosophically the Christian articles of faith, and demonstrated their untenableness. This work was addressed to Christians more than to Jews, and was particularly intended for the perusal of Spaniards of high rank whose friendship Chasdaï Crescas enjoyed. Hence it was written not in Hebrew but in Spanish, which the author employed with ease, and its tone was calm and moderate. Chasdaï Crescas set forth the unintelligibility of the doctrines of the Fall, the Redemption, the Trinity, the Incarnation, the Immaculate Conception, and Transubstantiation, and examined the value of baptism, the coming of Jesus, and the relation of the New Testament to the Old, with dispassionate deliberation, as if he did not know that he was dealing with questions which might at any moment light the fires of an auto-da-fé. At about the same time an accomplished Marrano, who had relapsed into Judaism, published a pungent attack on Christianity and the new-Christians. In the entire history of Judæo-Christian controversy no such stinging satire had been produced on the Jewish side as that now issued by the physician, astronomer, historical student, and grammarian Profiat Duran. During the bloody persecution of 1391 in Catalonia, Profiat Duran, otherwise Isaac ben Moses, or, as he called himself in his works, Efodi (Ephodæus), had been forced to simulate conversion to Christianity. He was joined by his friend David Bonet Buen-Giorno. Both resolved at a convenient opportunity to abandon their hated mask and emigrate to Palestine, where they could freely acknowledge Judaism. Their affairs being arranged, Profiat Duran traveled to a seaport town in the south of France, and there awaited his friend. The latter, in the meantime, was sought out by or came across the Jew-hating apostate, Solomon Paul de Santa Maria, and was prevailed upon to remain a Christian. What was Profiat Duran's astonishment when he received a letter announcing, with much exultant vaporing, the definite acknowledgment of Christianity by En Bonet, who exhorted him also to remain in the pale of his adopted faith. The letter contained an enthusiastic panegyric of Paul de Santa Maria, who had been taken into the favor of the king of Castile. Profiat Duran could not remain silent. In reply, he inflicted punishment on his friend, and more particularly on the proselytizing Paul, in an epistle characterized by the keenest irony, which has not yet lost its sting. It pretends to assent to everything advanced by Bonet, and to confirm him in his resolve to remain a Christian. "Be not ye like your fathers" (Altehi ka-Abothecha) is the refrain throughout, and so artfully is this admonition employed that Christians used it (under the title Alteca Boteca) as an apology for Christianity. Whilst thus pretending to