Still another noted scholastic, Guillaume d'Auvergne (1228-29), was to rule the see of Paris while its chief church was building. He finished the northwest tower, which differed slightly in size and details from that to the south; across the face of the former are ten statues, whereas nine only are set before its companion tower. Perhaps a change of architects caused the disparity, or it may be that when the houses were cleared away for the erection of the north tower, more space was available. Bishop Guillaume d'Auvergne's writings show him to have been one of the most original thinkers in the XIII century, a theologian, a philosopher, a mathematician, and one versed in Arab and in Greek literature. He became for St. Louis a kind of prime minister in ecclesiastical business, and, like the king, he founded hospitals and houses of charity. There is a charming page in Joinville's reminiscences concerning this able man. A priest expressed his doubts to him on the Eucharist. Bishop Guillaume asked if he tried to resist the temptations, and he replied that he did so with all his force. "Now I," said the good bishop, "have not a single doubt about the Real Presence. I am like the fortress of Montleheri, safe in the heart of France, far from the danger line; but you, who fight unceasingly, are like the king's fortress of Rochelle in Poitou, on the frontier. Now, of us two, whom will the king most honor for guarding his fortresses?"
Peasant and prince, crusader and scholar, humanist and mathematician, men of exemplary lives, born rulers and guides, such were the builders of Notre Dame of Paris, and their ability and sincerity live eternally in their work.[82] They gave free wing to the soul in raising their great church, while they cheerfully accepted the human law of working within limits. No cathedral in France shows more clearly the relation between builders and building, more clearly vindicates the ideals of its age. The partisan historian may cite his instances to prove that the religion of that age was superstitious. While Notre Dame stands, such charges are refuted. It is a historical document as potent for the vindication of the truth as the _Divina Commedia_ itself.