The philosopher, Joseph Ibn-Shem Tob (born 1400, died a martyr 1460), who was a voluminous writer, a popular preacher, and a frequenter of the Castilian court, also entered the lists against Christianity to expose the fallacy and unreasonableness of its dogmas. In his frequent intercourse with Christians of distinction, both clerical and lay, he found it necessary to make himself thoroughly acquainted with Christian theology that he might adduce cogent arguments in reply to those who wished to convert him, or in his presence made the oft-reiterated statement of the falsity of Judaism. Occasionally a regular controversy in defense of his creed was forced upon him. The fruits of his studies and thought he committed to writing in the shape of a small treatise, entitled "Doubts of the Religion of Jesus," in which he criticised with unsparing logic the dogmas of Original Sin, Salvation, and Incarnation. Besides, he wrote, for the instruction of his brethren, a detailed commentary on Profiat Duran's satire on Christianity, and made available for them, by means of a Hebrew translation, Chasdaï Crescas' polemical work against the Christian religion, originally written in Spanish. Strange to say, the Spanish Jews preferred, as a rule, Hebrew books to those in the language of their adopted country. Among the authors of polemical works against Christianity a contemporary of Joseph Ibn-Shem Tob deserves special mention. History has hitherto forgotten Chayim Ibn-Musa, from Bejar, in the neighborhood of Salamanca (born about 1390, died about 1460), a physician, versifier and writer, who had access to the Spanish court and the grandees through his medical skill, and so, frequent opportunities of discussing questions of doctrine with ecclesiastics and learned laymen. A colloquy preserved by Chayim Ibn-Musa illustrates the spirit which prevailed in Spain before the hateful Inquisition silenced all freedom of speech. A learned ecclesiastic once asked Ibn-Musa why, if Judaism, as he maintained, was the true faith, the Jews could not possess themselves of the Holy Land and Jerusalem? Ibn Musa replied that they had lost their country through the sins of their fathers, and could regain it only by perfect atonement and purgation. He, in turn, propounded a question: Why are the Christians no longer in possession of the Holy Sepulcher? and why does it, together with all the sites associated with the Passion, continue in the hands of Mahometan infidels, notwithstanding that Christians, by means of confession and absolution, and through the medium of the nearest available priest, can free themselves at any moment from sin? Before the ecclesiastic could bethink himself of a suitable reply, a knight, who had formerly been in Palestine, interposed: The Mahometans are the only people who deserve to possess the site of the Temple and the Holy Land, for neither Christians nor Jews hold houses of prayer in so much honor as they.