Of all the Olympian gods, Hermes is the most “down to earth” (epichthonios), a deity who eschews the heavenly, watery, and underworld abodes in favor of the places inhabited by mortals. His patronage of travelers grows not only from his territorial concerns but also from his role as a herdsman, for Hermes accompanies and protects the traveler just as the shepherd guides and watches over his flocks. In the last book of the Iliad (24.334-38), Zeus asks him to protect Priam on his mission into the Greek camp because Hermes loves “to be a man’s companion.” Roadside cairns and guideposts marking the path belonged to Hermes, and multi-headed images of him, like those of Hekate, were placed at crossroads. The Classical herm, a stone image of Hermes consisting of a squared pillar with a bearded head of Hermes on top, a crossbar where the “shoulders” should be, and erect male genitals halfway down, probably developed from wooden versions used as markers. Around 520, Hipparchos, brother of the Athenian tyrant Hippias, set up stone herms marking the halfway points on the roads from each Attic village to the agora, where the Altar of the Twelve Gods had been designated the city center. Edifying verses supplied by Hipparchos himself, such as “walk with just intent” and “deceive not a friend” were carved upon the herms. These were enthusiastically received, and soon so many herms were clustered at the principal entrance to the agora that the spot became known as “the Herms.” Magistrates and victorious generals like Kimon dedicated them, and one in particular, known as Hermes Agoraios, had its own altar.4
From the late sixth century on, herms served the Athenians and other Greeks not only as milestones and boundary markers, but also as guardians, warding off any evil spirits (or thieves) who might try to enter a home. They became an important focus of popular piety, and were regularly saluted, anointed with oil, and garlanded. Scenes of private sacrifice before herms are very common on Attic figured vases. Thus it was a terrible shock for the Athenians when they awoke one morning to find that someone had gone about the city knocking the noses and genitals from their beloved herms. This sacrilege took place on the eve of the Sicilian expedition in 415, and augured ill for the Athenian war effort.5