The year 1982 marked the 350th anniversary of the publication of Galileo's Dialogue Concerning the Two Chief World Systems, a work that was to have a tragic impact on the astronomer's life, and also on the relations between science and religion. It was the publication of the Dialogue that precipitated the trial of Galileo before the Inquisition on charges of teaching the Copernican system, which had been condemned in 1616. The book sets forth the inadequacies of the Ptolemaic system and the superiority of the Copernican for “saving the appearances” of celestial motion, but it does not press openly for acceptance of the theory. An earlier writing of Galileo, the Letter to Madame Christina of Lorraine, Grand Duchess of Tuscany, referred to in short as the Letter to Christina, does just that. It was written in 1615 before the opinion on Copernicanism was delivered, and written, moreover, to dissuade the Church from condemning Copernicus's De revolutionibus of 1543.