I have had two purposes in view in these studies. One purpose was the tracing of a religious movement, profoundly interesting in itself, as a great side current of the Reformation. The other purpose was the discovery of the background and environment of seventeenth century Quakerism. There can be little doubt, I think, that I have here found at least one of the great historical sources of the Quaker movement. This volume, together with my _Studies in Mystical Religion_, will at any rate {vi} furnish convincing evidence that the ideas, aims, experiences, practices, and aspirations of the early Quakers were the fruit of long spiritual preparation. This movement, as a whole, has never been studied before, and my work has been beset with difficulties. I have been aided by helpful monographs on individual "Reformers," written mainly by German and French scholars, who have been duly credited at the proper places, but for the most part my material has been drawn from original sources. I am under much obligation to my friend, Theodor Sippell of Schweinsberg, Germany. I am glad to announce that he is preparing a critical historical study on John Everard and the Ranters, which will throw important light on the religious ideas of the English Commonwealth. He has read my proofs, and has, throughout my period of research, given me the benefit of his extensive knowledge of this historical field. I wish to express my appreciation of the courtesy and kindness which I have received from the officials of the University Library at Marburg. William Charles Braithwaite of Banbury, England, has given me valuable help. My wife has assisted me in all my work of research. She has read and re-read the proofs, made the Index, and given me an immense amount of patient help. I cannot close this Preface without again referring to the inspiration of my invisible friend, John Wilhelm Rowntree, in whose memory this series was undertaken. HAVERFORD, PENNSYLVANIA, _January_ 1914. {vii} CONTENTS PAGE INTRODUCTION WHAT IS "SPIRITUAL RELIGION" . . . . . . . . . . . . . . . xi CHAPTER I THE MAIN CURRENT OF THE REFORMATION . . . . . . . . . . . 1 CHAPTER II HANS DENCK AND THE INWARD WORD . . . . . . . . . . . . . . 17 CHAPTER III TWO PROPHETS OF THE INWARD WORD: BUeNDERLIN AND ENTFELDER 31 CHAPTER IV SEBASTIAN FRANCK: AN APOSTLE OF INWARD RELIGION . . . . . 46 CHAPTER V CASPAR SCHWENCKFELD AND THE REFORMATION OF THE "MIDDLE WAY" 64 CHAPTER VI SEBASTIAN CASTELLIO: A FORGOTTEN PROPHET . . . . . . . . . 88 {viii} CHAPTER VII COORNHERT AND THE COLLEGIANTS--A MOVEMENT FOR SPIRITUAL RELIGION IN HOLLAND . . . . . . . . . . . . . 104 CHAPTER VIII VALENTINE WEIGEL AND NATURE MYSTICISM . . . . . . . . . . 133 CHAPTER IX JACOB BOEHME: HIS LIFE AND SPIRIT . . . . . . . . . . . . 151 CHAPTER X BOEHME'S UNIVERSE . . . . . . . . . . . . . . . . . . . . 172