Please note that Mommsen uses the AUC chronology (Ab Urbe Condita), i.e. from the founding of the City of Rome. You can use this reference table to have the B.C. dates
Courageously it made its dispositions for the
double conflict, the Transalpine Gauls and Insubres against the
troops of Papus, the Alpine Taurisci and the Boii against the
Sardinian infantry; the cavalry combat pursued its course apart on
the flank. The forces were in numbers not unequally matched, and the
desperate position of the Gauls impelled them to the most obstinate
resistance.
But the Transalpine Gauls, accustomed only to close
fighting, gave way before the missiles of the Roman skirmishers; in
the hand-to-hand combat the better temper of the Roman weapons placed
the Gauls at a disadvantage; and at last an attack in flank by the
victorious Roman cavalry decided the day.
The Celtic horsemen made
their escape; the infantry, wedged in between the sea and the three
Roman armies, had no means of flight. 10,000 Celts, with their king
Concolitanus, were taken prisoners; 40,000 others lay dead on the
field of battle; Aneroestus and his attendants had, after the Celtic
fashion, put themselves to death.