It is not within the purpose of this paper to appraise the historical significance which the Council of Trent held for the consolidation of Catholic doctrine on all the points of dogmatic and sacramental theology that had been put into question by the religious innovators. Nor shall we examine the role which its measures of canonical legislation played in the great process of spiritual and disciplinary renewal which eventually determined the position of the Catholic Church in the modern world. We propose rather to turn our attention to the great goal which the Council did not reach: the restoration of the one Respublica Christiana, of the Catholic unity which prior to the sixteenth century had been the only conceivable form of Christian religious existence. To the eye of the historian, it is true, the rift in Western Christendom appears quite obviously prepared by the developments of two centuries preceding Luther's challenge. The exile of Avignon; the great schism; the constitutional unrest of the conciliar epoch of Constance and Basel; the political realism by which Renaissance popes had sought above all to consolidate their position as Italian territorial rulers; the growth of the national states and national sovereignties; the ferment of humanistic ideologies—they all were alarming and distressing symptoms of the radical disintegration of mediaeval unity.