Lake Nemi

Lake Nemi fills a small volcanic crater in the Alban Hills a short distance southeast of Rome, its still, round basin giving it the poetic name Ovid uses in the Fasti, speculum Dianae, "Diana's mirror." On its northern shore stood one of central Italy's most important sanctuaries to Diana, worshipped there specifically as Diana Nemorensis, "Diana of the Wood," a cult that predates Roman control of the site and drew worshippers, including a documented Roman aristocratic dedication by a consul in the fourth century BCE, from well beyond the immediate area. The sanctuary combined worship of Diana as huntress and protector of wild places with cults of Egeria, a water nymph associated in Roman legend with king Numa Pompilius, and of Virbius, a minor woodland deity later mythographers identified with the Greek hero Hippolytus, reborn after his death and hidden in Diana's grove.

Archaeological excavation of the sanctuary site, carried out from the nineteenth century onward, has recovered a substantial body of votive offerings, statuary and architectural remains confirming the site's importance across several centuries of use, extending from the pre-Roman period through the Roman imperial era. The lake's own physical isolation, ringed by wooded hills with no natural outlet visible at the surface, likely reinforced its reputation as an especially numinous and enclosed sacred landscape distinct from more urban Roman cult sites.

What made Nemi's sanctuary famous, both in antiquity and to modern readers, was the singular rule governing its chief priest, the Rex Nemorensis, "King of the Wood." Ancient sources, principally later Roman authors reporting an already old custom, describe the priesthood as held by a runaway slave who first proved his eligibility by breaking off a branch from a particular sacred tree in Diana's grove, and who then held office only for as long as he could defend it, since any successful challenger who killed him in single combat became the new Rex Nemorensis in his place. The office thus combined sanctuary, since escaped slaves were otherwise liable to recapture, with constant lethal risk, an arrangement ancient writers themselves treated as strange enough to comment on directly.

James Frazer opened his enormously influential comparative study of magic and religion, The Golden Bough, with exactly this custom, using the riddle of why a priesthood should be won and held by murder as the starting question for a wide ranging, if now largely superseded, theory linking sacred kingship, the death and renewal of a divine or semi-divine figure, and the fertility of the land across many cultures. Whatever the custom's precise origin, which remains debated among modern scholars of Roman religion, Nemi's Rex Nemorensis is one of the most distinctive institutions of religious violence documented anywhere in the classical Roman religious record, and it made an otherwise modest local sanctuary into one of the most discussed sites in the entire history of the comparative study of religion.