Aegeria, or Egeria, is an ancient Latin Goddess of healing, springs, sacred knowledge and inspiration Who has close ties with Diana; She may in fact originally have been an aspect of Diana as a healing and birth Goddess. She was worshipped in at least three places, in Rome itself and in the neighborhood south-east of the city, each site possessing a spring known for its healing qualities. She is also a Goddess of inspiration and sacred wisdom, for She was said to have inspired Her lover, the Roman King Numa, to reform or institute many important religious practices. Aegeria's name seems to be akin to the Latin verb gero, "to bear" or "to carry"; one form of this verb leads to the English "gestation", meaning pregnancy, though it would appear that the actual Latin terms for pregnancy are not related to gero. Pregnant women did pray to Her for a healthy pregnancy and easy childbirth, and Aegeria's name is sometimes glossed as "Giver of Life", though "She Who Bears Children" would probably work, too. She was considered one of the Camenae, prophetic nymphs who were also concerned with birth.
As a Goddess of Springs Aegeria was also a prophetess and was said to predict the future of the newborn babies She watched over. Another aspect relating to springs was Her possession of divine wisdom and the knowledge of the sacred; for springs, as water which comes out of the earth, represent the subconscious knowledge of magic and dreams rising to the surface. Plutarch calls Aegeria an Oak-tree Goddess, which according to the Greek system would make Her specifically a Dryad; and oaks, like those at Dodona which were sacred to Zeus, are connected with prophecy too.
Aegeria was worshipped alongside Diana not far from the city of Aricia in Latium, at Lake Nemi, a gorgeous lake set in the crater of an extinct volcano, about 17 miles south-east of Rome. Within the crater Aegeria had a famous spring that flowed from its walls into the lake, cascading down in several waterfalls, and which was powerful enough to run several mills in medieval times. The sanctuary of Diana was located in a small flat plain on the northern side of the lake, which looks to me (though I am no geologist) to be the remnant of a second, more shallow crater. Diana's sanctuary does not seem to have had any temple or other buildings there before the 4th century BCE, though other finds date further back, and Her worship there is taken as a given to be far older. The grove of Diana there (in which, incidentally, the most important tree, and the one involved in its most famous rite, that of the Golden Bough, was an oak) was said to have been a meeting place for the Latin peoples. Called Diana Nemorensis ("Diana of the Woods") at Nemi, Her temple complex included a set of baths used for therapeutic purposes which were filled with the waters from Aegeria's spring. Many votive figures—some depicting body parts in need of healing, or mothers with children—were found there; the mother and child figurines were most likely offered in the hopes of conceiving a child, or as prayers for a healthy pregnancy and easy delivery.
Aegeria's second spring is located in the modern Parco della Caffarella, a park about 3 miles southeast of the center of Rome, which is likely the valley that was known in ancient times as the Egeriae vallis, the "Vale of Egeria" and through which the Almo river (the modern Almone) flows before joining with the Tiber in Rome. In this valley sacred to Aegeria is still to be found a nymphaem, or spring-fed grotto, which in the 2nd century CE was given a marble revamping complete with a statue of Aegeria in a niche. The waters of this spring were diverted into a couple of pools before flowing all of 400 feet into the Almo; the first of them, a large rectangular deal, was called the lacus Salutaris, or "Health-giving lake", evidentially believed to have healing powers.
Her third spring was in Rome itself by the porta Capena, a gate in the Servian wall on the south side of town through which the via Appia passed; it was shared with the Camenae, the prophetic water Goddesses with Whom Aegeria was associated. This water, too, was said to have beneficial and health-giving properties. Though Aegeria was only connected with the Camenae at a late date (They appear to have been the original owners of the spring), the association of the area with Aegeria (and Her lover King Numa) has lasted into modern times, for about a half-mile from the porta Capena is the Parco Egerio, as well as the Piazzale Numa Pompilio.
The main Roman legend of Aegeria that has come down to us concerns Her long and serious affair with the second King of Rome, Numa Pompilius. After the death of his first wife Tatia, who was the daughter of the Sabine King Titus Tatius (which puts her in the generation of women abducted and assaulted by the Romans in the episode famously called the Rape of the Sabine Women), he met Aegeria, and taken with Her intelligence and divine beauty, just as She was taken with his love of nature and gentle ways, they became lovers. For many years Numa visited Her at night by Her spring in the grove, and She taught him proper religious rituals and customs. With the knowledge of the sacred that She imparted to him, he established or reformed quite a few Roman religious practices, for instance—he built a temple to Janus, God of Beginnings, and set up the worship of Fides (Goddess of Faith) and Terminus (God of Boundaries); he instituted several priesthoods, like the pontifices, the high priests of Rome who oversaw public and private ritual, and the Vestal Virgins who tended the sacred flame at the heart of Rome; he established flamens (priests specific to a Deity) for Mars, Jupiter, and Quirinus (a.k.a. the deified Romulus); he reformed the calendar and set up holidays; and he instituted the proper rites of burial. Aegeria's ability to inspire Numa may have led to the later association of the Camenae (including Aegeria) with the Muses, the Greek Goddesses of Inspiration.
Aegeria was said to come to Numa in a visible form, and from the emphasis placed on this in the stories it would seem that that type of visible manifestation was an exception with the Gods rather than the rule. Apparently, however, She did not accord this honor to anyone else. In one tale, Numa invited some friends over for dinner one night. Despite being King, Numa was a man of sparse and simple habits, and he served his friends good plain food on plates made of clay, with drink in wooden cups. But Aegeria came to them then, and though the other guests could not see Her, they knew She was present among them because everything took on a shine—the plain food became a marvellous feast served on silver plates with golden goblets. The guests, who probably had not really believed Numa when he had said his girlfriend was a Goddess, were then convinced of the truth.
Numa was honored in Roman legend as a peaceful and deeply religious man (as you may have guessed from the long list above, just about any religious institution in Rome was credited to him, and I imagine the list got longer with the years); he was remembered as a quiet and thoughtful type who had only reluctantly accepted the Kingship. When he died, after a long and peaceful reign, Aegeria was heartbroken and left Her spring near Rome to live in the grove of Diana at Lake Nemi in Aricia. There She wept so much that Diana turned Her into a spring.
Of course the Romans had it backward, in that the historic worship of Aegeria probably came from Aricia to Rome, not the other way round, but then the Romans were happy to co-opt any legend that could be used to glorify their early history, for example by claiming that their religious practices came straight from the Gods. Aegeria may very well have been a Sabine Goddess as much as She was a Latin one—Numa in the legends represents the Sabine faction of early Rome, and, according to Varro, Her cult partner Diana was of Sabine origin too.
Back in Aricia at Lake Nemi, Aegeria was considered one of a triad with Diana and the forest God Virbius. Virbius was said to have originally been one Hippolytus, a favorite of Artemis, who had died and been brought back to life by the divine healer Asklepios. However, this was against sacred law, and so Artemis whisked him off to Aricia and renamed him Virbius, to disguise who He had been (though, honestly, if I know this, how could Zeus not?) His first order of business in Aricia was to establish the great temple to Diana (Artemis) in the crater at lake Nemi, and the second to marry Aegeria. This tale is another example of the Roman prediliction for rewriting their early history to sound more glamorous, in this case by connecting a local story with the noble and glorious Greeks. In reality Virbius was a native Latin woodland God Who had been associated with Diana and Aegeria at Nemi from early times. In some works, Virbius is even said to be the consort of Diana Herself.
Some have seen in Aegeria an early aspect of Diana, as They were both very concerned with childbirth and healing, both associated with the same very ancient cult site at Nemi, and both, depending on the tale, considered to have Virbius as a consort. That alone is a good argument for the ancient origins of the cult at Nemi, for Diana is almost always called "chaste" or "virginal" in other tales. In some traditions, Diana's cult at Nemi was said to have been founded by either Egerius Baebius, Egerius Laevius, or Manius Egerius; their suspiciously familiar names, and the status they have as founders, do seem to indicate Aegeria's importance as a double for Diana and not merely as a nymph of a spring.
Diana/Aegeria at Nemi might also plausibly be connected with a darker, chthonic version of the Goddess: another name for Lake Nemi, besides the usual poetic name of speculum Dianae, "the mirror of Diana", was Triviae lacus, "the Lake of Trivia", a form of Diana as Hecate, the triple crossroads Goddess of the Moon, Earth, and Underworld. Further, it is not uncommon for spring Goddesses to have Underworld links, as springs bubble up direct from underearth and represent a connexion between the land of the living and that of the dead. And, the site of Her cult at Nemi was literally inside the crater of a volcano; and volcanoes were associated in the Roman mind with entrances to the Underworld—like the entrance believed to be in the Phlegraean Fields, a volcanic area frighteningly close to Naples (which has Vesuvius on its other side, yikes!), or the entrance mentioned in Virgil at Lake Avernus in the same region, which, like Nemi, is a lake in the crater of an extinct volcano. And, perhaps it is mere coincidence, but the Latin meaning of Laevius, the name of one of the founders, is "ill-omened", "on the left hand", or "sinister"; and Manius Egerius was connected (at least in the popular mind) with the manes, the spirits of the dead or Gods of the Underworld.
Also called: Egeria. Aegeria seems to be the older form.