evidence: One of Aristotle's more famous quotes was, "All men naturally desire knowledge" ("πάντες ἄνθρωποι τοὺ εἰδέναι ὀρὲγονται φύσει") (Aristotle, Metaphysics, 1.980a.22). As a classical Greek philosopher, an ideology like this is required for producing many outstanding achievements. He was known as a philosopher, artist, and scientist. Greek-born, he started with humble beginnings by attending Plato's academy; becoming one of the most widely known philosophers in human history. Aristotle wrote many books, one of them was On the Heavens (ΠΕΡΙ ΟΥΡΑΝΟΥ). We are still not sure when the book was officially written, but it was around 350 BCE. His ideas included the four common elements on Earth (earth, air, fire, water), and also a fifth element which we will discuss later. The book revolves around his observations regarding the universe. The theories of Aristotle were groundbreaking for his time and were used until roughly the 1500s CE until the writings of Copernicus.