During his residence at Ferrara, Calvin was not satisfied with combating the errors of those who surrounded him: he did not forget France, to which his heart was always attached; and he watched, although from afar, the friends he had left there. The superstitions of Italy and the profane spirit displayed by the priests in the midst of their relics and empty ceremonies, produced the same effect upon him as upon Luther, and made him all the more desirous to see his fellow-countrymen withdraw from the authority of the pope. He was therefore deeply moved by the news which reached him at this time. Nicholas Duchemin, with whom he had lived at Orleans, whose character he esteemed, and of whom he had said, 'that he was dearer to him than his life,' had been appointed official or ecclesiastical judge, which brought him into close relations with the Roman clergy and worship. Calvin was alarmed and sent him a letter which, revised and enlarged, was published under this title: _How we must avoid the papal ceremonies and superstitions, and observe the Christian religion with purity_.[799] 'I do not mean,' said Calvin to his friend, 'that you should make a conscience of things which it is not in your power to escape, and with regard to which you should be free. I do not forbid your entering the temples which surround you, although numberless examples of impiety are witnessed in them daily. Although the images are consecrated to detestable sacrileges, I do not forbid you to look at them. It would not even be in your power, for the streets are full of a multitude of idols. But have a care lest a too great license should make you overstep the bounds of liberty.'[800] Duchemin was very sensible of the danger, and wishing to be at the same time faithful to the Gospel, and to preserve an advantageous appointment, had put this question to Calvin: 'How can I keep myself pure among the pollutions of Babylon?' Calvin showed him, as he had shown François, that the mass was the most dangerous enemy. 'Do not believe,' he said, 'in that conjuror who approaches the altar and begins to play his tricks, now turning this side, now that; at one time resting motionless, at another muttering his magic murmurs, by means of which he pretends to draw Christ down from heaven to make reconciliation between God and man, and thus substitute himself for the Saviour dead and raised again.'[801]