The first authentic knowledge we have of Bruno was when he was twenty-two years old. He was then a Dominican monk, and he is brought to our attention because he distinguished himself by incurring the displeasure of his superiors. His particular offense was that he had declared, "The infallibility of the Pope is only in matters spiritual, and does not apply to the science of material things." Strangely enough, these words of Bruno are almost identical with words recently expressed by Cardinal Satolli. The difference in their reception is owing to a mere matter of a few hundred years. Truth is a question of time and place. Bruno was banished for his temerity, and Satolli wears the red hat. Verily, yesterday's heresy is today's orthodoxy. * * * * * The attitude of the Church toward the teachings of Copernicus, after the death of the man, was one of patronizing pity. Instead of putting his great book, "Revolutions of the Heavenly Bodies," on the "Index," the wiser plan was adopted of paying no attention to it. Occasionally, however, the subject was broached by some incautious novitiate, and then the custom was to treat the Copernican Theory as a mere hypothesis, and its author as a mental defective. Bruno would not have it so. To him it was a very important matter whether the sun revolved around the earth as the priests taught, or the earth revolved around the sun as set forth in the work of Copernicus. He came to the conclusion that Copernicus was right, and said so. It was ordered that he should cease lecturing on the subject of astronomy and apply himself to spiritual matters. He argued that he should be allowed to think and speak what he pleased about the stars, since the whole matter was one of opinion, and even the Pope did not know, positively, the final facts of astronomy, and if the Copernican Theory was a hypothesis, so also was the Ptolemaic Theory held by the Church. It will be seen that Copernicus and Bruno were very different in temperament: one was gentle, diplomatic, cautious; the other was headstrong, firm and full of argument. Bruno was given his choice: to cease the study of astronomy or to lay aside the Dominican frock. The hardihood of the young man was seen in that he unfrocked himself, thinking that once outside of the order he was not responsible to a superior and could teach what he pleased, so long as it was not "heresy."