Numa Pompilius

In Roman mythology, Numa Pompilius was the second king of Rome, succeeding after Romulus. His wife, the goddess Egeria, met him by a spring in a sacred grove and taught him how to be a wise legislator. He was later celebrated for his piety.

Wishing to show his favour, the god Mars caused a shield to fall from the sky on the Palatine Hill, which had letters of prophecy written on it, and in which the fate of Rome as a city was tied up. Recognizing the importance of this sacred shield, King Numa had eleven matching shields made. These shields were the ancilia, the sacred shields of Mars, which were carried each year in a procession by the Salii priests.

When Numa Pompilius died in 673 BC, Egeria changed him into a well, located in the forest of Aricia, holy to Diana, in Latium.