It was not until four years later that trouble arose, the ecclesiastical authorities taking alarm at the persistence with which Galileo proclaimed the truth of the Copernican doctrine. That their opposition was grounded, as is constantly assumed, upon a fear lest men should be enlightened by the diffusion of scientific truth, it is obviously absurd to maintain. On the contrary, they were firmly convinced, with Bacon and others, that the new teaching was radically false and unscientific, while it is now truly admitted that Galileo himself had no sufficient proof of what he so vehemently advocated, and Professor Huxley after examining the case avowed his opinion that the opponents of Galileo “had rather the best of it”. But what, more than all, raised alarm was anxiety for the credit of Holy Scripture, the letter of which was then universally believed to be the supreme authority in matters of science, as in all others. When therefore it spoke of the sun staying his course at the prayer of Joshua, or the earth as being ever immovable, it was assumed that the doctrine of Copernicus and Galileo was anti-Scriptural; and therefore heretical. It is evident that, since the days of Copernicus himself, the Reformation controversy had done much to attach suspicion to novel interpretations of the Bible, which was not lessened by the endeavours of Galileo and his ally Foscarini to find positive arguments for Copernicanism in the inspired volume. Foscarini, a Carmelite friar of noble lineage, who had twice ruled Calabria as provincial, and had considerable reputation as a preacher and theologian, threw himself with more zeal than discretion into the controversy, as when he sought to find an argument for Copernicanism in the seven-branched candlestick of the Old Law. Above all, he excited alarm by publishing works on the subject in the vernacular, and thus spreading the new doctrine, which was startling even for the learned, amongst the masses who were incapable of forming any sound judgment concerning it. There was at the time an active sceptical party in Italy , which aimed at the overthrow of all religion, and, as Sir David Brewster acknowledges (Martyrs of Science), there is no doubt that this party lent Galileo all its support.
In these circumstances, Galileo, hearing that some had denounced his doctrine as anti-Scriptural, presented himself at Rome in December, 1615, and was courteously received. He was presently interrogated before the Inquisition , which after consultation declared the system he upheld to be scientifically false, and anti-Scriptural or heretical, and that he must renounce it. This he obediently did, promising to teach it no more. Then followed a decree of the Congregation of the Index dated 5 March 1616, prohibiting various heretical works to which were added any advocating the Copernican system.