Late Classic Greek philosophy was dominated by Plato and Aristotle. Plato believed in eternal forms and advocated for rule by philosopher kings, while Aristotle focused on logic and scientific investigation. The 16th century work The School of Athens by Raphael spread the erroneous idea that Renaissance Europe's culture directly descended from Classical Greece. In reality, Greek scientific thought diffused eastward during the Hellenistic period, and these ideas were later maintained in Persia and highly developed in Islamic civilizations before spreading to Europe over 1400 years later. Philip of Macedon expanded his kingdom in northern Greece and consolidated the southern Balkan peninsula until his assassination in 323 BCE. His son, Alexander the Great, then led military campaigns from 336 to 323