The value of the source-book has long been recognized in the teaching of general history. In ecclesiastical history quite as much use can be made of the same aid in instruction. It is hoped that the present book may supply a want increasingly felt by teachers employing modern methods in teaching ecclesiastical history. It has grown out of classroom work, and is addressed primarily to those who are teaching and studying the history of the Christian Church in universities and seminaries. But it is hoped that it may serve the constantly increasing number interested in the early history of Christianity.

In the arrangement of the selected illustrative material, a chronological analysis and grouping of topics has been followed, according to the lines of treatment employed by K. Mueller, F. Loofs, Von Schubert in his edition of Moeller's text-book, and by Hergenroether to some extent. The whole history of ancient Christianity has accordingly been divided into comparatively brief periods and subdivided into chapters and sections. These divisions are connected and introduced by brief analyses and characterizations, with some indications of additional source material available in English.

A bibliography originally prepared for each chapter and section has been omitted. When the practical question arose of either reducing the amount of source material to admit a bibliography, or of making the book too expensive for general use by students, the main purpose of the book determined the only way of avoiding two unsatisfactory solutions of the problem, and the bibliography has been omitted. In this there may be less loss than at first appears. The student of ecclesiastical history is fortunately provided with ample bibliographical material for the ancient Church in the universally available theological and other encyclopaedias which have very recently appeared or are in course of publication, and in the recent works on patristics. Possibly the time has come when, in place of duplicating bibliographies, reliance in such matters upon the work of others may not be regarded as mortal sin against the ethics of scholarship. A list of works has been given in the General Bibliographical Note, which the student is expected to consult and to which the instructor should encourage him to go for further information and bibliographical material.

The book presupposes the use of a text-book of Church history, such as those by Cheetham, Kurtz, Moeller, Funk, or Duchesne, and a history of doctrine, such as those of Seeberg, Bethune-Baker, Fisher, or Tixeront. Readings in more elaborate treatises, special monographs, and secular history may well be left to the direction of the instructor.

The translations, with a few exceptions which are noted, are referred for the sake of convenience to the Patrology of Migne or Mansi's Concilia. Although use has been freely made of the aid offered by existing translations, especially those of the Ante-Nicene and Post-Nicene Fathers, yet all translations have been revised in accordance with the best critical texts available. The aim in the revision has been accuracy and closeness to the original without too gross violation of the English idiom, and with exactness in the rendering of ecclesiastical and theological technical terms. Originality is hardly to be expected in such a work as this.

An author may not be conscious of any attempt to make his selection of texts illustrate or support any particular phase of Christian belief or ecclesiastical polity, and his one aim may be to treat the matter objectively and to render his book useful to all, yet he ought not to flatter himself that in either respect he has been entirely successful. In ecclesiastical history, no more than in any other branch of history, is it possible for an author who is really absorbed in his work to eliminate completely the personal equation. He should be glad to be informed of any instance in which he may have unwittingly failed in impartiality, that when occasion presented he might correct it. The day has gone by in which ecclesiastical history can not be treated save as a branch of polemical theology or as an apologetic for any particular phase of Christian belief or practice. It has at last become possible to teach the history of the Christian Church, for many centuries the greatest institution of Western Europe, in colleges and universities in conjunction with other historical courses.

This volume has been prepared at the suggestion of the American Society of Church History, and valuable suggestions have been gained from the discussions of that society. To Professor W. W. Rockwell, of Union Theological Seminary, New York, Professor F. A. Christie, of Meadville Theological School, the late Professor Samuel Macauley Jackson, of New York, and Professor Ephraim Emerton, of Harvard University, I have also been indebted for advice. The first two named were members with me of a committee on a Source-Book for Church History appointed several years ago by the American Society of Church History.

That the book now presented to the public may be of service to the teacher and student of ecclesiastical history is my sincere wish. It may easily happen that no one else would make just the same selection of sources here made. But it is probable that the principal documents, those on which the majority would agree and which are most needed by the teacher in his work, are included among those presented. There are, no doubt, slips and defects in a book written at intervals in a teacher's work. With the kind co-operation of those who detect them, they may be corrected when an opportunity occurs.

JOSEPH CULLEN AYER, JR.