Otho having started for Brixellum, the honours of supreme command devolved on his brother Titianus, while the real power and control were in the hands of the prefect Proculus. Celsus and Paullinus, as no one made any use of their skill, did but screen with their idle title of general the blunders of others. The tribunes and centurions were perplexed to see that better men were despised, and that the most worthless carried the day. The common soldiers were full of eagerness, but liked to criticise rather than to obey the orders of their officers. It was resolved to move the camp forward to the fourth milestone from Bedriacum, but it was done so unskilfully, that though it was spring, and there were so many rivers in the neighbourhood, the troops were distressed for want of water. Then the subject of giving battle was discussed, Otho in his despatches ever urging them to make haste, and the soldiers demanding that the Emperor should be present at the conflict; many begged that the troops quartered beyond the Padus should be brought up. It is not so easy to determine what was best to be done, as it is to be sure that what was done was the very worst.
They started for a campaign rather than for a battle, making for the confluence of the Padus and Addua, a distance of sixteen miles from their position. Celsus and Paullinus remonstrated against exposing troops wearied with a march and encumbered with baggage to any enemy, who, being himself ready for action and having marched barely four miles, would not fail to attack them, either when they were in the confusion of an advance, or when they were dispersed and busy with the work of entrenchment. Titianus and Proculus, overcome in argument, fell back on the Imperial authority. It was true that a Numidian had arrived at full gallop with an angry message from Otho, in which the Emperor, sick of delay and impatient of suspense, sharply rebuked the inactivity of the generals, and commanded that matters should be brought to an issue.
The same day, while Caecina was engaged on the construction of a bridge, two tribunes of the Praetorian Guard came to him and begged an interview. He was on the point of hearing their proposals and sending back his own, when the scouts arrived at headlong speed with the news that the enemy were close at hand. The address of the tribunes was thus abruptly terminated. Thus it remained uncertain whether deception, or treason, or some honourable arrangement, had been in their thoughts. Caecina dismissed the tribunes and rode back to the camp. There he found that Fabius Valens had given the signal for battle, and that the troops were under arms. While the legions were casting lots for the order of march, the cavalry charged, and, strange to say, were kept only by the courage of the Italian legion from being driven back on the entrenchments by an inferior force of Othonianists. These men, at the sword's point, compelled the beaten squadron to wheel round and resume the conflict. The line of the Vitellianists was formed without hurry, for, though the enemy was close at hand, the sight of their arms was intercepted by the thick brushwood. In Otho's army the generals were full of fear, and the soldiers hated their officers; the baggage-wagons and the camp-followers were mingled with the troops; and as there were steep ditches on both sides the road, it would have been found too narrow even for an undisturbed advance. Some were gathering round their standards; others were seeking them; everywhere was heard the confused shouting of men who were joining the ranks, or calling to their comrades, and each, as he was prompted by courage or by cowardice, rushed on to the front, or slunk back to the rear.
From the consternation of panic their feelings passed under the influence of a groundless joy into languid indifference, some persons spreading the lie that Vitellius' army had revolted. Whether this rumour was circulated by the spies of Vitellius, or originated in treachery or in accident among the partisans of Otho, has never been clearly ascertained. Forgetting their warlike ardour, the Othonianists at once greeted the foe; as they were answered by an angry murmur, they caused apprehensions of treachery in many of their own side, who did not know what the greeting meant. Then the enemy's line charged with its ranks unbroken, in strength and in numbers superior; the Othonianists, scattered and weary as they were, met the attack with spirit. The ground was so entangled with trees and vineyards that the battle assumed many forms. They met in close and in distant conflict, in line and in column. On the raised road they stood foot to foot, they pushed with their bodies and their shields, and ceasing to throw their javelins, they struck through helmets and breastplates with swords and battle-axes. Recognising each other and distinctly seen by the rest of the combatants, they were fighting to decide the whole issue of the war.
In an open plain between the Padus and the road, two legions happened to meet. On the side of Vitellius was the 21st, called the Rapax, a corps of old and distinguished renown. On that of Otho was the 1st, called Adjutrix, which had never before been brought into the field, but was high-spirited, and eager to gain its first triumph. The men of the 1st, overthrowing the foremost ranks of the 21st, carried off the eagle. The 21st, infuriated by this loss, not only repulsed the 1st, and slew the legate, Orfidius Benignus, but captured many colours and standards from the enemy. In another quarter the 13th legion was put to flight by a charge of the 5th. The 14th was surrounded by a superior force. Otho's generals had long since fled and Caecina and Valens strengthened their army with the reserves.
New reinforcements were supplied by Varus Alfenius with his Batavians.
