Titus Livius (Livy), The History of Rome, Book 2
Rev. Canon Roberts, Ed.

53. The¹ domestic conflicts came to an end; war began again with the Veientines, with whom the Sabines had formed an armed league. The Latin and Hernican auxiliaries were summoned, and the consul P. Valerius was sent with an army to Veii. He at once attacked the Sabine camp, which was situated in front of the walls of their allies, and created such confusion that while small bodies of the defenders were making sorties in various directions to repel the attack, the gate against which the assault had been first made was forced, and once inside the rampart it became a massacre rather than a battle. [2] The noise in the camp penetrated even to the city, and the Veientines flew to arms, in a state of as great alarm as if Veii itself was taken. Some went to the help of the Sabines, others attacked the Romans, who were wholly occupied with their assault on the camp. [3] For a few moments they were checked and thrown into confusion; then, forming front in both directions, they offered a steady resistance while the cavalry whom the consul had ordered to charge routed the Tuscans and put them to flight. [4] In the same hour, two armies, the two most powerful of the neighbouring states, were overcome.

Whilst this was going on at Veii, the Volscians and Aequi had encamped in the Latin territory and were ravaging their borders. The Latins, in conjunction with the Hernici drove them out of their camp without either a Roman general or Roman troops. [5] They recovered their own property and obtained immense booty in addition. Nevertheless, the consul C. Nautius was sent from Rome against the Volscians. They did not approve, I think, of the custom of allies carrying on war in their own strength and on their own methods, without any Roman general or army. [6] There was no kind of injury or insult that was not practised against the Volscians; they could not, however, be driven to fight a regular battle.