With regard to the share which I have taken in the production of this volume, only a very few words of explanation are necessary. As mentioned above, I aided my departed friend in correcting the proof sheets of the Syriac text from p. To the end; and he made it his last request to me that I would undertake to usher the work into the world. To this I consented somewhat reluctantly, simply from a consciousness of my total incompetence to do it and him justice. As a mere linguistl am not his equal, nor is my historical knowledge to be compared with his. He had studied the questions connected with this volume for years and from every point of view; whereas I was new to them, having scarcely ventured at all into that particular field of history, nor having, for the present at least, the necessary leisure to do so. I have therefore confined myself entirely to a careful revision of the Syriac texts, which I have collated line for line with the original manuscripts. In this way I have been able, I hope, to note every error or misprint of any consequence but I have not thought it necessary to swell the list of errata, and thereby uselessly augment the size of the volume, by pointing out every instance in which a mark of punctuation has been omitted or mis placed. Nor have I deemed it worth while to spend time in the revision of the translation and notes, being aware that the attentive reader can easily correct for himself the comparatively few and tri?ing misprints that occur in them.