On the accession of a new Pope (1623), Urban VIII., who had been his friend as Cardinal Barberini, Galileo, after eight years of silence, thought that he might now venture to publish his great work on the Ptolemaic and Copernican systems, especially as the papal censor also had been his friend. But the publication of the book was delayed nearly two years, so great were the obstacles to be surmounted, and so prejudiced and hostile was the Church to the new views. At last it appeared in Florence in 1632, with a dedication to the Grand Duke,--not the Cosimo who had rewarded him, but his son Ferdinand, who was a mere youth. It was an unfortunate thing for Galileo to do. He had pledged his word not to advocate the Copernican theory, which was already sufficiently established in the opinions of philosophers. The form of the book was even offensive, in the shape of dialogues, where some of the chief speakers were his enemies. One of them he ridiculed under the name of Simplicio. This was supposed to mean the Pope himself,--so they made the Pope believe, and he was furious. Old Cardinal Bellarmine roared like a lion. The whole Church, as represented by its dignitaries, seemed to be against him. The Pope seized the old weapons of the Clements and the Gregories to hurl upon the daring innovator; but delayed to hurl them, since he dealt with a giant, covered not only by the shield of the Medici, but that of Minerva. So he convened a congregation of cardinals, and submitted to them the examination of the detested book. The author was summoned to Rome to appear before the Inquisition, and answer at its judgment-seat the charges against him as a heretic. The Tuscan ambassador expostulated with his Holiness against such a cruel thing, considering Galileo's age, infirmities, and fame,--all to no avail. He was obliged to obey the summons. At the age of seventy this venerated philosopher, infirm, in precarious health, appeared before the Inquisition of cardinals, not one of whom had any familiarity with abstruse speculations, or even with mathematics.