My aim in this book is to bring together materials for a judgment of the change which came over Europe in the sixteenth century, to which the name of "The Reformation" is loosely given. I have attempted to do this from a strictly historical point of view,- by which I mean that I have contented myself with watching events and noting the gradual development of affairs. I have taken the history of the Papacy as the central point for my investigation, because it gives the largest opportunity for a survey of European affairs as a whole. I have not begun with the actual crisis itself, but have gone back to trace the gradual formation of opinions which were long simmering below the surface before they found actual expression. I purpose, if opportunity should be given me, to continue my survey in succeeding volumes to the dissolution of the Council of Trent.