The author of this 1930 volume maintains that the first two and a half years of the pontificate of Pius IV, during which the continuation of the Council of Trent and the maintenance of its earlier decrees were secured against strong French and German opposition, constituted the critical period which finally determined the ultimate orientation of the Counter-Reformation. This thesis is worked out in detail in regard to the French efforts to prevent the continuation of the Tridentine Council and to force the Counter-Reformation into different channels from those desired by Rome, efforts which were largely inspired by the Cardinal of Lorraine around whom the narrative is hung. In addition, an attempt is made to appreciate the Cardinal's personality and to understand his ecclesiastical standpoint.