Aristotle was a Greek philosopher best known as the student of Plato and the teacher of Alexander the Great. He wrote and taught concerning government, poetry, physics, logic, biology and ethics, among many other things. He was one of the three great Greek scholars, along with Plato and Socrates, and a founder of modern Western philosophy. He joined Plato's Academy at the age of eighteen and remained there until Plato's death twenty years later. He then went on a biological and zoological research trip with Xenocrates and married the daughter of Phythias. After the death of his wife, he was invited to tutor Alexander the Great. He remained in Athens and founded another school of philosophy. He wrote on such a wide variety of subjects that his writings have been called the encyclopedia of Greek knowledge, and it has been suggested that Aristotle was the last man to know all there was to know during the time that he lived. He died of natural causes on his own farm.