It has been supposed, without any satisfactory evidence, that Urban may have been influenced by less creditable motives. Salviati and Sagredo being well-known personages, it was inferred, that Simplicio must also have a representative. The enemies of Galileo are said to have convinced his holiness that Simplicio was intended as a portraiture of himself; and this opinion received some probability from the fact, that the peripatetic disputant had employed many of the arguments which Urban had himself used in his discussions with Galileo. The latest biographer of Galileo[27] regards this motive as necessary to account for "the otherwise inexplicable change which took place in the conduct of Urban to his old friend;"--but we cannot admit for a moment the truth, of this supposition. The church had been placed in hostility to a powerful and liberal party, which was adverse to its interests. The dogmas of the Catholic faith had been brought into direct collision with the deductions of science. The leader of the philosophic band had broken the most solemn armistice with the inquisition: he had renounced the ties of gratitude which bound him to the pontiff; and Urban was thus compelled to intrench himself in a position to which he had been driven by his opponents. The design of summoning Galileo before the inquisition, seems to have been formed almost immediately after the publication of his book; for even in August, 1632, the preliminary proceedings had reached the ears of the grand duke Ferdinand. The Tuscan ambassador at Rome was speedily acquainted with the dissatisfaction which his sovereign felt at these proceedings; and he was instructed to forward to Florence a written statement of the charges against Galileo, in order to enable him to prepare for his defence. Although this request was denied, Ferdinand again interposed; and transmitted a letter to his ambassador, recommending the admission of Campanella and Castelli into the congregation of ecclesiastics by which Galileo was to be judged. Circumstances, however, rendered it prudent to withhold this letter. Castelli was sent away from Rome, and Scipio Chiaramonte, a bigotted ecclesiastic, was summoned from Pisa to complete the number of the judges.