Protagoras (circa 490 BC - 420 BC) was a pre-Socratic Greek philosopher and is numbered as one of the Sophists by Plato. In his dialogue Protagoras, Plato credits him with having invented the role of the professional Sophist or teacher of virtue. He is also believed to have created a major controversy during ancient times through his statement that "man is the measure of all things." This idea was revolutionary for the time and contrasted with other philosophical doctrines that claimed the Universe was based on something objective, outside the human influence. Plato (circa 424 BC - 348 BC) was a philosopher in Classical Greece. He was also a mathematician, student of Socrates, writer of philosophical dialogues, and founder of the Academy in Athens, the first institution of higher learning in the Western world. Along with his mentor, Socrates, and his student, Aristotle, Plato helped to lay the foundations of Western philosophy and science.