The ancients held different opinions about the form, dimensions, the proportion of land to water, of the earth, and as to whether it was motionless, around which all the universe revolved, as the great center, and of supreme importance, or whether it was merely a satellite revolving around the sun. It seems flat and the heavenly bodies seem to revolve around it. Others thought the earth was a sphere because “the sphere is the most perfect form; it was the center of the universe because that is the place of honor; and it is motionless, because motion is less dignified than rest.” Some believed that the earth is round and rests upon the ocean. Homer (900 B. C.) taught that the earth is flat, and so, too, did some of the learned men of Greece and Rome, in the Augustan age. The great Church of Rome, of unequaled influence and power, taught that the earth is flat and the center of the universe and interdicted, and for centuries punished as heretics, those denying the infallibility of the Popes and teaching otherwise. It is probable that about 600 B. C., Thales of Miletus, one of the “Seven Wise Men of Greece,” a famous astronomer and geometer, was the first to teach that the earth is round. About 550 B. C. Pythagoras, the renowned Greek philosopher and mathematician, taught that “the earth is a globe which admits of antipodes; that it is in motion; is not the center of the universe, but revolves around the sun.” Plato, Aristotle, Hipparchus, Pliny, Cicero, Virgil, Ovid, Eratosthenes and many others, the most eminent scholars of their times, believed that the earth is a sphere; and Eratosthenes, an Alexandrian philosopher, astronomer, geometer and geographer about 210 B. C. thought that he had not only proved that by scientific astronomical observations but also the speed of the earth in its revolutions; its magnitude and also the relative proportion of its constituent elements of land and water. Claudius Ptolemy, about 150 A. D., a celebrated Alexandrian astronomer, geographer and mathematician, held the opinion and promulgated it, that the earth is a sphere and that the sun, planets and stars revolve around it as the grand center. He was the founder of the Ptolemaic System which was almost universally received for 1,350 years, when the system of Copernicus (a revival of the system of Pythagoras) permanently displaced it, notwithstanding the violent opposition, extending to persecution, of the Church of Rome against it.