In 1543, Nicolaus Copernicus revived Aristarchus' Heliocentric System in an attempt to rid Ptolemy's geocentric system of the un-Aristotelian idea of the Equant. He desired to create a model of the planets that would please the mind as well as preserving appearances. Rather than reinstate the ideal of the Aristotelian World View, he was to set the stage for its overthrow after nearly 2000 years of supremacy, and within two centuries give birth to the modern world. This lecture describes the astronomical world from the end of the classical age until the birth of Copernicus, and then describes his revolutionary idea of putting the Sun, and not the Earth, at the center of the Universe. Recorded 2007 Oct 9 in 1000 McPherson Lab on the Columbus campus of The Ohio State University. NOTE: Due to a recorder malfunction, only the first 15 minutes of this lecture was recorded.