Platonic Academy
The idea of the philosopher's beard gained traction when in 155 BCE three philosophers arrived in Rome as Greek diplomats: Carneades, head of the Platonic Academy; Critolaus of Aristotle's Lyceum; and the head of the Stoics, Diogenes of Babylon. "In contrast to their beautifully clean-shaven Italian audience, these three intellectuals all sported magnificent beards." Thus the connection of beards and philosophy caught hold of the Roman public imagination.