Diana of Nemi: the sacred grove, the priest-king and the mirror of the Moon
The sanctuary of Diana Nemorensis near Aricia, the rex Nemorensis, the torches of the Ides of August and the temple on the Aventine in ancient Rome.
In the Alban Hills, south of Rome, a small volcanic lake reflects the sky like a dark sheet of glass. The ancients called it Speculum Dianae, the mirror of Diana, and on its shores stood one of the most revered sanctuaries of Latium, that of Diana Nemorensis, Diana of the sacred grove, the nemus from which the name Nemi itself derives. Here the Latin goddess showed her oldest and most mysterious features.
The king of the grove
The sanctuary, in the territory of Aricia, was served by a remarkable priest, the rex Nemorensis. According to ancient sources, including Servius' commentary on the Aeneid, the office fell to a runaway slave who managed to kill the priest in office after breaking off a branch of a sacred tree. The new king then lived in fear of suffering the same fate. Suetonius relates that Caligula, believing that the king of the day had held the office too long, sent a stronger challenger against him.
This custom made a deep impression on the Scottish anthropologist James George Frazer, who in 1890 made it the starting point of his famous The Golden Bough, a vast work on magic and religion. Many of his interpretations were later disputed or abandoned by scholars, but the king of Nemi has remained ever since one of the best-known figures of Roman religion.
The torches of the Ides of August
Diana's main festival fell on the Ides of August, the thirteenth of the month. Ovid, in the Fasti, recalls women wearing garlands who carried lit torches from Rome to the grove of Aricia to fulfil a vow that had been granted. Statius too, in the Silvae, describes the lake lit by torches on that same occasion. Night light, lake and goddess formed a single scene that the ancients easily associated with the Moon.
On the same day Rome celebrated the anniversary of the temple of Diana on the Aventine, which Livy attributes to King Servius Tullius. The temple had a political value, since it had been conceived as a common sanctuary of the Latin peoples. In the imperial period the Ides of August were also a holiday for slaves, a link that some connect with the goddess's role as protector of those who lived on the margins.
Diana, Trivia and Luna
Catullus' poem 34, a choral hymn to Diana, sums up her identities: the goddess is Lucina for women in labour, Trivia of the crossroads, and she is called Luna for her borrowed light, «notho lumine». That definition condenses an ancient piece of knowledge, that the Moon does not shine with its own light, and a theology that made Diana a goddess of three spheres, sky, earth and underworld.
The lake of Nemi also held two great ships from the time of Caligula, recovered between 1928 and 1932 by partially draining the basin and then destroyed by fire in 1944. Today a museum on the shore preserves their memory. The sacred grove has vanished, but the lake still reflects the Moon, as in the days when it was the goddess's mirror.