Not content with thus securing the friendship of the pope, Galileo endeavoured to bespeak the good-will of the cardinals towards the Copernican system. He had, accordingly, many interviews with several of these dignitaries; and he was assured, by cardinal Hohenzoller, that in a representation which he had made to the pope on the subject of Copernicus, he stated to his holiness, "that as all the heretics considered that system as undoubted, it would be necessary to be very circumspect in coming to any resolution on the subject." To this remark his holiness replied,--"that the church had not condemned this system; and that it should not be condemned as heretical, but only as rash;" and he added, "that there was no fear of any person undertaking to prove that it must necessarily be true."
The recent appointment of the abbé Castelli, the friend and pupil of Galileo, to be mathematician to the pope, was an event of a most gratifying nature; and when we recollect that it was to Castelli that he addressed the famous letter which was pronounced heretical by the inquisition, we must regard it also as an event indicative of à new and favourable feeling towards the friends of science. The opinions of Urban, indeed, had suffered no change. He was one of the few cardinals who had opposed the inquisitorial decree of 1616, and his subsequent demeanour was in every respect conformable to the liberality of his early views. The sincerity of his conduct was still further evinced by the grant of a pension of one hundred crowns to Galileo, a few years after his visit to Rome; but there is reason to think that this allowance was not regularly paid.
The death of Cosmo, whose liberality had given him both affluence and leisure, threatened Galileo with pecuniary difficulties. He had been involved in a "great load of debt," owing to the circumstances of his brother's family; and, in order to relieve himself, he had requested Castelli to dispose of the pension of his son Vincenzo: but he was now alarmed at the prospect of losing his salary as an extraordinary professor at Pisa. The great youth of Ferdinand, who was scarcely of age, induced Galileo's enemies, in 1629, to raise doubts respecting the payment of a salary to a professor who neither resided nor lectured in the university; but the question was decided in his favour, and we have no doubt that the decision was facilitated by the friendly recommendation of the pope, to which we have already referred.