The reign of the second Roman king, Numa, is remembered, on account of his influence on the affairs of religion. He instituted many of the religious ceremonies and several classes of priests, and was regarded as the founder of the religious institutions of Rome.
During the reign of the third king, Tullus Hostilius, a war was carried on with Alba Longa. The issue of this war was decided, so the story goes, by a combat between the three Horatii, champions of the Romans, and the three Curiatii, champions of Alba—resulting in the triumph of the Romans and the submission of Alba to the Roman power.
The fourth king, Ancus Marcius, was a Sabine, the grandson of Numa. He too was a man of peace, but was drawn into a war with several of the Latin cities. Having subdued them, he transferred their inhabitants to the Aventine hill.