Egeria was a nymph attributed a legendary role in the early history of Rome as a divine consort and counselor of Numa Pompilius, the second king of Rome, to whom she imparted laws and rituals pertaining to ancient Roman religion. Her name is used as an eponym for a female advisor or counselor.

Numa Pompilius was the legendary second king of Rome, succeeding Romulus after a one-year interregnum. He was of Sabine origin, and many of Rome's most important religious and political institutions are attributed to him, such as the Roman calendar, Vestal Virgins, the cult of Mars, the cult of Jupiter, the cult of Romulus, and the office of pontifex maximus.