Numa Pompilius
Ancus was the son of Marcius (whose father, also named Marcius, had been a close friend of Numa Pompilius, who may be identified with Numa Marcius, and Pompilia (daughter of Numa Pompilius). Ancus Marcius was also the grandson of Numa and therefore a Sabine. According to Festus, Marcius had the surname of Ancus from his crooked arm ("ancus" signifying "bent" in Latin).