A word must be added with reference to the notes. These have been placed at the ends of the volumes because the author believes the best plan will be to read the text of each chapter before looking at the notes that bear upon it, and also in part because he did not wish any one to feel that he was parading his discussions and citations. The notes contain supplementary material designed to make the work a critical as well as a narrative history, and contain also specific references to the sources on which the text is based. These references involved a most annoying problem. When one's citations are limited in number and proceed in single file, as it were, they can be handled easily. But in the present instance as many as 1800 documents were used for a chapter, not a few of which were cited more than once; and each sentence of the text--to speak broadly--resulted from comparing a number of sources. Under these conditions the usual method would have produced a repellent mass of references, perhaps greater in extent than the text itself, which would have been very expensive to print and from their multiplicity would have been extremely inconvenient. Where that method appeared feasible it was adopted, but as a rule the references have been grouped by paragraphs or topics. In many cases, however, pains have been taken to indicate in the text itself the basis of important statements, and further hints will be found in the notes. The reader can thus always ascertain in general the basis of the text, and will find specific references wherever the author has thought it likely they would be desired. The special student will wish to look up all the citations bearing on any topic that interests him. No doubt the plan is somewhat unsatisfactory, but after studying the subject for a dozen years the author feels sure that any other would have been more so.[P.5]