Of Abdera;[1] son of Artemon, or of Maeandrides or Neandrius; some write that he was from Teos. Originally he was a porter, but on meeting Democritus[2] he fell in love with discourse, became a philosopher and then turned to rhetoric. He was the first to be called a sophist, and the first to invent eristic arguments and make a contest of speeches, and to charge his pupils (100 minas - for which reason he was nicknamed 'Speech for Hire'). He was the teacher of the rhetor Isocrates.[3]
He was the first to divide all discourse into four: wish, question, answer, command. After him others made a division into seven, as follows: narration, question, answer, command, statement, wish, appellation. Alcidamas[4] says there are four kinds of discourse: assertion, denial, question, address.
Protagoras' books were burned by the Athenians, because he once made a speech which began like this: 'About the gods I can know nothing - neither that they exist, nor that they do not exist'. He was older than the philosopher Plato.[5] He was the teacher of Prodicus of Ceos[6] and many others.