It is true that in this great and generous effort to secure the freedom of the human soul men in some measure lost their way. They demanded and in a measure they succeeded in asserting the freedom of the religious organization, as against the temporal organization, but in doing this they went perilously near to denying the freedom of the individual spiritual experience. They went perilously near to denying it, but they never wholly forgot it. The Church claimed and exercised an immense authority in religion, so immense an authority that it might easily seem as though there were no place left for the freedom of the individual judgement and conscience. And yet that was not the case. The theory of excommunication that is set out in the canonical literature of the Middle Ages has generally been carelessly studied and imperfectly understood. It was the greatest and most masterful of the Popes, Innocent III, who laid down in memorable phrases which are embodied in the great collection of the Decretals, that if a Christian man or woman is convinced in his own mind and conscience that it would be a mortal sin to do or to leave undone some action, he must follow his own conscience even against the command of the authorities of the Church, and must submit patiently to Church censures and even excommunication; for it may well happen that the Church may condemn him whom God approves, or approve him whom God condemns.[24] This is no isolated or exceptional opinion, but is the doctrine which is constantly laid down in the canonical literature.[25] It is, I think, profoundly true to say that when men at last revolted against what seemed to them the exaggerated claims of the Church, when they slowly fought their way towards toleration and religious freedom, they were only asserting and carrying out its one most vital principle, the principle of the independence or autonomy of the spiritual life; the modern world is only fulfilling the Middle Ages. I do not continue to develop this aspect of the progress of western civilization, not because it is unimportant, for indeed it is perhaps the greatest and most significant aspect of mediaeval life, but because it is well known to you, and indeed, it has generally been insisted on to such a degree as to obscure the other aspects of progress in the Middle Ages, with which we must deal. * * * * * And first I would ask you to observe that it was in these centuries that there were laid over again the foundations of the social and political order of civilization, and that there were devised those forms of the political order upon which the structure of modern society is founded.