Socrates taught Plato...Plato taught Aristotle...Aristotle taught Alexander the Great. In Greek philosophy there was a special bond between teacher and student that often became physical. It's not believed that Plato passed this tradition down because he wrote against it; hence, "platonic relationship", but it he did--that was the inspiration for the meme. So...there ya go. Now you know everything you need to know about Greek philosophers. :)