Beards grow when dihydrotestosterone wakes facial follicles
A beard is hair on the jaw, chin, lips, cheeks and neck, grown mostly by adult men, though some women develop one through a condition called hirsutism. Societies have prized it as a mark of wisdom, virility or status, or dismissed it as scruffy. Ancient Rome did both within a few centuries.
Growth starts at puberty, when dihydrotestosterone, made from testosterone, stimulates facial follicles; the same hormone drives balding, testosterone levels shift with the seasons, and genes set the pace. Because beards mark one sex without aiding reproduction directly, biologists class them as a secondary sexual characteristic. Charles Darwin suggested in The Descent of Man that sexual selection produced them, and later studies found most women rate bearded men as more attractive. Other researchers point to dominance signalling, since a beard makes the jaw look bigger, and debate which pressure mattered more.
Ancient styling was elaborate. Phoenicians wore rows of tight curls from ear to ear, and Assyrians and Babylonians used oil, tongs and curling irons to build tiers of ringlets. Egyptian men usually shaved, but high officials sometimes grew chin hair dyed with henna, and rulers of either sex wore a metal false beard, held on by a ribbon and gold chin strap, as a sign of sovereignty. For Israelites, shaving the corners of the beard was a mourning custom. In Homer's Greece a supplicant would touch the beard of the person being begged, and a smooth face read as effeminate.
Rome came late to razors. Pliny says P. Ticinius brought the first barber around 299 BCE, and Scipio Africanus was reportedly the first Roman to shave. Soon a long beard looked squalid: censors made the exiled M. Livius shave before rejoining the Senate. Hadrian, ruling from 117, became the first emperor with a full beard, perhaps to hide facial scars, and emperors kept them until Constantine.
Beards also became the uniform of philosophy. Three bearded Greek envoys, Carneades, Critolaus and Diogenes of Babylon, impressed a clean-shaven Roman crowd in 155 BCE. Cynics wore theirs long and dirty, Stoics trimmed and washed them, and Epictetus declared he would sooner be beheaded than shave, at a time when Domitian had Apollonius of Tyana forcibly shorn.
Source: Beard
