most eminent of our Oriental scholars. The Apology is absolutely unique of its kind. In antiquity, daring, rhetoric and power, we have nothing in the annals of the Mahometan controversy at all approaching it. And any research that might throw light upon the origin of the argument, the life and circumstances of our Author, the authenticity of the work, and the genuineness of the text handed down to us, must possess not only a literary interest, but in some respects a practical and important bearing on the same struggle, which is being waged to-day, as engaged the labours of Abdallah the H�shimite and Abd al Mas�h Al Kindy, the Christian, in the days of Al M�m�n.

I have to express my acknowledgments to Prof. Ignatius Guidi of Rome, to Dr. Fritz Hommel of M�nchen, and to Dr. Steinschneider of Berlin, for their very kind assistance in the prosecution of this inquiry. To the first, I feel specially grateful for his goodness in copying out for me the entire controversy in which Abu Y�suf al Kindy appears as an opponent of the doctrine of the Trinity.

Letter of THE H�SHIMITE to Al Kindy (pp. 2-23).

THE letter of the Mahometan Advocate opens with the salutation of peace and mercy. This, which is unusual with Mahometans when addressing Infidels, he justifies by the example of the Prophet, who made no difference, as to his style of address, between Zimmies (protected Jews and Christians) and true Believers.¹ He then speaks of the esteem in which Al Kindy was held by the Caliph, his cousin, and of his own warm regard for him. He dwells on his friend's noble birth, and expresses admiration for his distinguished piety, culture, and learning. It was in full accord with the teaching of the Prophet that he now invited him to embrace Islam, and discuss in a kindly and gracious spirit the merits of their respective creeds.² He was himself familiar with Christianity in all its forms. He had read the Jewish and Christian Scriptures, the several books of which he