says Muratori, 'so infected Renée with his errors that it was never possible to extract from her heart the poison she had drunk.'[770] [Sidenote: A CHRISTIAN WALK.] An open Christian walk was difficult at a court where popery and worldliness ruled together. Hence Renée felt keenly the need of directions in harmony with the Word of God; and in her difficulties and agonies, at the times when she was about to faint, 'as if she was sunk in water almost over her head,' she had recourse to the evangelical theologian. Calvin then invited her always to walk 'forwards, in order that the gifts of God might increase in her.' 'The main point,' as he wrote to her some time after, 'is that the holy doctrine of our Master should so transform us in mind and heart, that His glory may shine forth in us by innocence, integrity, and holiness.'[771] Some of the most illustrious divines of Roman-catholicism have been, in France and other countries, the directors of princes; but there was a great difference between them and the reformer. That practical evangelist, whom Romish controversialists and others have reproached with speaking of nothing but doctrines, urged the daughter of Louis XII. to 'seek after _innocence_, _integrity_, and _holiness_.' The relations of Calvin with the duchess lasted all his life, and they were always marked with frankness and respect. Touched with a zeal so Christian and so pure, she loved and honored him, 'as long as he lived,' says Theodore Beza, 'as an excellent instrument of the Lord.'[772] Even when he could no longer hold a pen on account of his extreme weakness, Calvin, borrowing the hand of his brother, wrote to her; and to her were addressed the last three French epistles of the reformer.[773] [Sidenote: THE COUNTESS OF MARENNES.]