the peace with Alba was not a lasting one. The Alban
dictator had incurred general odium through having entrusted the fortunes of the State to three soldiers, and this had an evil effect upon his weak character.
As straightforward counsels had turned out so unfortunate, he tried to recover the popular favour by resorting to crooked ones, and as he had previously made peace his aim in war , so now he sought the occasion of war in peace. He recognised that his State possessed more courage than strength, he therefore incited other nations to declare war openly and formally, whilst he kept for his own people an opening for treachery under the mask of an alliance.
The people of Fidenae, where a Roman colony existed, were induced to go to war by a compact on the part of the Albans to desert to them; the Veientines were taken into the plot.
When Fidenae had broken out into open revolt, Tullus summoned Mettius and his army from Alba and marched against the enemy. After crossing the Anio he encamped at the junction of that river with the Tiber
The army of the Veientines had crossed the Tiber
at a spot between his camp and Fidenae. In the battle they formed the right wing near the river, the Fidenates were on the left nearer the mountains. Tullus formed his troops in front of the Veientines, and stationed the Albans against the legion of the Fidenates. The Alban
general showed as little courage as fidelity; afraid either to keep his ground or to openly desert, he drew away gradually towards the mountains.
When he thought he had retired far enough, he halted his entire army, and still irresolute, he began to form his men for attack, by way of gaining time, intending to throw his strength on the winning side.
Those Romans who had been stationed next to the Albans were astounded to find that their allies had withdrawn and left their flank exposed, when a horseman rode up at full speed and reported to the king that the Albans were leaving the field. In this critical situation, Tullus vowed to found a college of twelve Salii and to build temples to Pallor and Pavor.
Then, reprimanding the horseman loud enough for the enemy to hear, he ordered him to rejoin the fighting line, adding that there was no occasion for alarm, as it was by his orders that the Alban
army was making a circuit that they might fall on the unprotected rear of the Fidenates.
At the same time he ordered the cavalry to raise their spears; this action hid the retreating Alban
army from a large part of the Roman infantry. Those who had seen them, thinking that what the king had said was actually the case, fought all the more keenly. It was now the enemies' turn to be alarmed; they had heard clearly the words of the king, and, moreover, a large part of the Fidenates who had formerly joined the Roman colonists understood Latin.
Fearing to be cut off from their town by a sudden charge of the Albans from the hills, they retreated. Tullus pressed the attack, and after routing the Fidenates, returned to attack the Veientines with greater confidence, as they were already demoralized by the panic of their allies.
They did not wait for the charge , but their flight was checked by the river in their rear. When they reached it, some, flinging away their arms, rushed blindly into the water, others, hesitating whether to fight or fly, were overtaken and slain. Never had the Romans fought in a bloodier battle.