490 BCE – 420 BCE) is 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 very revolutionary for the time and contrasting to other philosophical doctrines that claimed the universe was based on something objective, outside the human influence.
