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
From: The History of Rome, by Theodor Mommsen
Translated with the sanction of the author by William Purdie Dickson
Disruption of the Rebels and Their Subjugation
This extreme step however was not needed; the disunion and the arrogance of the robber-bands sufficed again to frustrate their successes. Once more the Celts and Germans broke off from the league of which the Thracian was the head and soul, in order that, under leaders of their own nation Gannicus and Castus, they might separately fall victims to the sword of the Romans. Once, at the Lucanian lake the opportune appearance of Spartacus saved them, and thereupon they pitched their camp near to his; nevertheless Crassus succeeded in giving employment to Spartacus by means of the cavalry, and meanwhile surrounded the Celtic bands and compelled them to a separate engagement, in which the whole body--numbering it is said 12,300 combatants--fell fighting bravely all on the spot and with their wounds in front.
Spartacus then attempted to throw himself with his division into the mountains round Petelia (near Strongoli in Calabria), and signally defeated the Roman vanguard, which followed his retreat But this victory proved more injurious to the victor than to the vanquished. Intoxicated by success, the robbers refused to retreat farther, and compelled their general to lead them through Lucania towards Apulia to face the last decisive struggle. Before the battle Spartacus stabbed his horse: as in prosperity and adversity he had faithfully kept by his men, he now by that act showed them that the issue for him and for all was victory or death.
Do you see any typos or other mistakes? Please let us know and correct them
Reference address : https://www.ellopos.net/elpenor/rome/5-02-rule-sullan-restoration.asp?pg=80