at Rome, Galileo went thither, confident that he would be able to convince the ecclesiastical authorities of the manifest truth of Copernicanism. He did not realize what theology was capable of. In February 1616 the Holy Office decided that the Copernican system was in itself absurd, and, in respect of Scripture, heretical. Cardinal Bellarmin, by the Pope's direction, summoned Galileo and officially admonished him to abandon his opinion and cease to teach it, otherwise the Inquisition would proceed against him. Galileo promised to obey. The book of Copernicus was placed on the Index. It has been remarked that Galileo's book on Solar Spots contains no mention of Scripture, and thus the Holy Office, in its decree which related to that book, passed judgment on a scientific, not a theological, question.
Galileo was silenced for a while, but it was impossible for him to be mute for ever. Under a new Pope (Urban VIII) he looked for greater liberty, and there were many in the Papal circle who were well disposed to him. He hoped to avoid difficulties by the device of placing the arguments for the old and the new theories side by side, and pretending not to judge between them. He wrote a treatise on the two systems (the Ptolemaic and the Copernican) in the form
