The History of Rome (1.15.2-1.15.6)

After securing their booty they returned with it to Veii, without entrenching a camp or waiting for the enemy. The Romans, on the other hand, not finding the enemy on their soil, crossed the Tiber, prepared and determined to fight a decisive battle.

On hearing that they had formed an entrenched camp and were preparing to advance on their city, the Veientes went out against them, preferring a combat in the open to being shut up and having to fight from houses and walls.

Romulus gained the victory, not through stratagem, but through the prowess of his veteran army. He drove the routed enemy up to their walls, but in view of the strong position and fortifications of the city, he abstained from assaulting it. On his march home-wards, he devastated their fields more out of revenge than for the sake of plunder.

The loss thus sustained, no less than the previous defeat, broke the spirit of the Veientes, and they sent envoys to Rome to sue for peace. On condition of a cession of territory a truce was granted to them for a hundred years.

These were the principal events at home and in the field that marked the reign of Romulus. Throughout-whether we consider the courage he showed in recovering his ancestral throne, or the wisdom he displayed in founding the City and adding to its strength through war and peace alike-we find nothing incompatible with the belief in his divine origin and his admission to divine immortality after death.