Protagoras (c. 490 – c. 420 BCE) was a Greek philosopher and sophist who was credited by Plato with inventing the role of the professional sophist.
An acquaintance of the Athenian statesman Perikles, Protagoras was invited to a symposium held at his residence in Athens. There, he participated in a debate with the playwright Hermippos, who urged him to drink more. Protagoras and Hermippos were later joined by the misthiosKassandra, who provided her thoughts about Kleon. A while later, Protagoras was one of the guests to greet Aspasia, Perikles' partner, upon her arrival.
During the Plague of Athens in 429 BCE, Protagoras was visited Perikles' residence again alongside his other associates.