The Gauls perceived what was now the object of the Romans, when it was too late: they took from the temple of their goddess the golden standards called the "immovable," and with their whole levy, 50,000 strong, they offered battle to the Romans.
The situation of the latter was critical: they were stationed with their back to a river (perhaps the Oglio), separated from home by the enemy's territory, and left to depend for aid in battle as well as for their line of retreat on the uncertain friendship of the Cenomani.
There was, however, no choice.

The Gauls fighting in the Roman ranks were placed on the left bank of the stream; on the right, opposite to the Insubres, the legions were drawn up, and the bridges were broken down that they might not be assailed, at least in the rear, by their dubious allies.
The Celts Conquered by Rome In this way undoubtedly the river cut off their retreat, and their way homeward lay through the hostile army.

But the superiority of the Roman arms and of Roman discipline achieved the victory, and the army cut its way through: once more the Roman tactics had redeemed the blunders of the general.

The victory was due to the soldiers and officers, not to the generals, who gained a triumph only through popular favour in opposition to the just decree of the senate.

Gladly would the Insubres have made peace; but Rome required unconditional subjection, and things had not yet come to that pass.