Numa Pompilius,, according to Roman legend, the second king of ancient Rome and successor to Romulus. He is said to have been a Sabine who reigned 715-673 B.C. As king, Numa is credited with trying to soften the warlike character of the Romans and to turn their interest to religion. According to tradition, he originated Roman religious customs and rites. Historians, however, believe that most of these developed over the course of centuries.