Ancile was the oval shield of the same the god Mars, which Jupiter offered to the king Numa Pompilius, the second in the history ruler of Rome. According to the messages, the capital city was to exist for as long as ancile was safe. On the advice of the nymph Egeria, Numa had eleven identical shields to prevent theft.
Priests Salii were guarding the shields. Every year in March and October they carried shields in solemn processions organized in honor of the god Mars, and in their full weaponry they performed an ancient war dance.