Aristotle (384–322 BC) was born in the city of Stagira. At the age of seventeen or eighteen he came to Athens and became a student at Plato's Academy, where he remained for twenty years. Later he was appointed head of the royal academy in the kingdom of Macedon, where he tutored, among others, the king's son, Alexander. By 335 BC, Aristotle had returned to Athens, where he established a school known as the Lyceum. He conducted courses at the Lyceum for twelve years, and it is believed that he wrote most of his works during that time. His works constitute the first comprehensive system of philosophical and empirical knowledge. His influence on all subsequent philosophy and science is profound; the medieval Muslim scholars called him the "First Teacher" and the Scholastics referred to him simply as "The Philosopher."