Plutarch, Otho
Bernadotte Perrin, Ed.

12. And now, for some reason, it was believed and rumoured among Otho's vanguard that the generals of Vitellius would come over to their side. Accordingly, when these drew near, Otho's men greeted them in a friendly fashion and called them fellow-soldiers. The enemy, however, returned the salutation in no kindly spirit, but with anger and hostile cries, so that those who had greeted them were dejected, and were suspected of treachery by the others on their side. [2] This was the first thing that threw Otho's men into confusion, and at a time when the enemy were close at hand. And besides, nothing else was done properly, since the baggage-train wandered about among the fighting men and caused great disorder. Moreover, the line of battle was often broken by the nature of the ground, which was full of trenches and pits, and in avoiding or going around these the men were compelled to engage their opponents promiscuously and in many detachments. [3] Only two legions (to use the Roman word), that of Vitellius called ‘Rapax’ (or Devourer) and that of Otho called ‘Adiutrix’ (or Helper), got out into a treeless and extended plain, engaged in full formation, and fought a regular battle for a long time. Otho's men were sturdy and brave, but were now for the first time getting a taste of war and fighting; those of Vitellius, on the other hand, had seen many battles and were used to them, but they were now old and past their prime.

[4] So Otho's men charged upon them, drove them back, and captured their eagle, killing nearly all who stood in the first rank; but the others, impelled by shame and anger, fell upon their foes, slew Orfidius, the commander of the legion, and seized many of their standards. Against Otho's gladiators, too, who were supposed to have experience and courage in close fighting, Alfenus Varus led up the troops called Batavians. [5] They are the best cavalry of the Germans, and come from an island made by the Rhine. A few of the gladiators withstood these, but most of them fled towards the river, where they encountered cohorts of the enemy in battle array, and in defending themselves against these, were cut off to a man. [6] But the praetorian soldiers fought more shamefully than any others. They did not even wait for their opponents to come to close quarters, but fled through the ranks of their still unvanquished comrades, filling them with fear and confusion. Notwithstanding all this, many of Otho's men conquered those who opposed them, forced their way through the victorious enemy, and regained their camp.