Thus officially "admonished" for his heresy, but not punished, in 1616, Galileo kept silence for some years, till in 1618 he published his (erroneous) theory of the tides, which he sent with an ironical epistle to the friendly Archduke Leopold of Austria, professing to be propounding a mere dream, disallowed by the official veto on Copernicus. [266] This, however, did him less harm than his essay Il Saggiatore ("The Scales"), in which he opposed the Jesuit Grassi on the question of comets. Receiving the imprimatur in 1623, it was dedicated to the new pope, Urban VIII, who, as the Cardinal Maffeo Barberini, had been Galileo's friend. The latter could now hope for freedom of speech, as he had all along had a number of friends at the papal court, besides many priests, among his admirers and disciples. But the enmity of the Jesuits countervailed all. They did not succeed in procuring a censure of the Saggiatore, though that subtly vindicates the Copernican system while professing to hold it disproved by the fiat of the Church; [267] but when, venturing further, he after another lapse of years produced his Dialogues on the Two Systems, for which he obtained the papal imprimatur in 1632, they caught him in their net. Having constant access to the pope, they contrived to make him believe that Galileo had ridiculed him in one of the personages of his Dialogues. It was quite false; but one of the pope's anti-Copernican arguments was there unconsciously made light of; and his wounded vanity was probably a main factor in the impeachment which followed. [268] His Holiness professed to have been deceived into granting the imprimatur; [269] a Special Commission was set on foot; the proceedings of 1616 were raked up; and Galileo was again summoned to Rome. He was old and frail, and sent medical certificates of his unfitness for such travel; but it was insisted on, and as under the papal tyranny there was no help, he accordingly made the journey. After many delays he was tried, and, on his formal abjuration, sentenced to formal imprisonment (1633) for teaching the "absurd" and "false doctrine" of the motion of the earth and the non-motion of the sun from east to west. In this case the pope, whatever were his motives, acted as a hot anti-Copernican, expressing his personal opinion on the question again and again, and always in an anti-Copernican sense. In both cases, however, the popes, while agreeing to the verdict, abstained from officially ratifying it, [270] so that, in proceeding to force Galileo to abjure his doctrine, the Inquisition technically exceeded its powers--a circumstance in which some Catholics appear to find comfort. Seeing that three of the ten cardinals named in the preamble to the sentence did not sign, it has been inferred that they dissented; but there is no good reason to suppose that either the pope or they wilfully abstained from signing. They had gained their point--the humiliation of the great discoverer.