Nicolaus Copernicus (1473–1543) changed how educated human beings viewed the world by constructing the heliocentric theory of Earth’s relation to our Sun. According to the heliocentric theory, which is now considered common knowledge, Earth and the other planets revolve around the Sun. This heliocentric theory replaced the Ptolemaic geocentric theory, which held that that the Sun and other planets revolve around Earth. Copernicus became dissatisfied with the Ptolemaic system after his travels in Italy at a time when there was a lively revival of interest in ancient Pythagorian theories about the metaphysical importance of number for all aspects of nature. The Ptolemaic system was not mathematically elegant. But in Copernicus’ day the Church subscribed to the Ptolemaic theory, because that was the description of the cosmos given in the Bible.