The revolution that ended the reign of beards occurred on September 30, 331 b.c., as Alexander the Great prepared for a decisive showdown with the Persian emperor for control of Asia. On that day, he ordered his men to shave. Yet from time immemorial in Greek culture, a smooth chin on a grown man had been taken as a sign of effeminacy or degeneracy. What can explain this unprecedented command? When the commander Parmenio asked the reason, according to the ancient historian Plutarch, Alexander replied, “Don’t you know that in battles there is nothing handier to grasp than a beard?” But there is ample cause to doubt Plutarch’s explanation. Stories of beard-pulling in battles were myth rather than history. Plutarch and later historians misunderstood the order because they neglected the most relevant fact, namely that Alexander had dared to do what no self-respecting Greek leader had ever done before: shave his face, likening himself to the demigod Heracles, rendered in painting and sculpture in the immortal splendor of youthful, beardless nudity. Alexander wished above all, as he told his generals before the battle, that each man would see himself as a crucial part of the mission. They would certainly see this more clearly if each of them looked more like their heroic commander.

Adapted from Of Beards and Men: The Revealing History of Facial Hair, by Christopher Oldstone-Moore, published by the University of Chicago Press in January