The work of the Council of Trent marks in more ways than one a turning-point in the history of the Church of Rome. During the half-century preceding the date of the council, the Protestant revolt had wrested from the control of Rome nearly half of the territory of Europe, and the authority of the Church had been shaken even in States still classed as Catholic. The calling together of the council was the result of a realisation on the part of the Papacy and its advisers that the Protestant advance could not be stayed by simple reassertions of the authority of Rome, or by threats or edicts of excommunication. The Church must prove its right to rule, must in fact justify its continued existence. The practice of the ecclesiastics must be brought into conformity with ecclesiastical teachings. The claim that the Pope was the Vicar of Christ, the Vice-Regent of the Almighty, could be made good only through presenting practical evidence that the work of the Church was guided by the divine precepts, and that the workers of the Church were really the children of God. The Council of Trent retained in its great Index the prohibition of the writings of Erasmus, but the reforms initiated by the council constituted a justification of the strictures of the great Hollander, and in not a few instances these reforms simply carried out his recommendations. The divines of Trent did not hesitate to characterise Luther and his associates as the “children of the devil,” but these same divines placed on record condemnations hardly less specific than those that had come from the preachers of Wittenberg, of the abuses and corruptions that had taken possession of the Church of Christ. If the work of the reformers of Trent could by any possibility have been brought about fifty years earlier, we may imagine that the theses of Luther might never have been posted, while the leaders of the Protestant reform would have had available for their great contest no adequate ammunition. It may at once, however, be admitted that the “ifs of history” are at best but futile guesses. It is safer to conclude that without such shaking up as was given by the Protestant revolt, the reformation within the Church would never have been undertaken, or would at least not have taken shape during the sixteenth century. It is possible even that the loss of half of its realm was necessary if the existence of the Church as an institution was to be maintained. The history of the succeeding century makes clear that the Catholic reformation was undertaken in good faith, and with a full measure of devotion and earnestness, and that it brought about a great revival in Christian spirit and a noteworthy advance in scholarship, in wisdom and administration, and in faithful service on the part of the rulers, and of zeal, faith, and good works among their flocks.