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
The patriotic party was very strong in this canton; but the old antagonism to the leading of the Arverni counterbalanced their influence-- to the most serious detriment of the insurrection, as the accession of the eastern cantons, particularly of the Sequani and Helvetii, was conditional on the accession of the Haedui, and generally in this part of Gaul the decision rested with them. While the insurgents were thus labouring partly to induce the cantons that still hesitated, especially the Haedui, to join them, partly to get possession of Narbo--one of their leaders, the daring Lucterius, had already appeared on the Tarn within the limits of the old province--the Roman commander-in-chief suddenly presented himself in the depth of winter, unexpected alike by friend and foe, on this side of the Alps.
He quickly made the necessary preparations to cover the old province, and not only so, but sent also a corps over the snow-covered Cevennes into the Arvernian territory; but he could not remain here, where the accession of the Haedui to the Gallic alliance might any moment cut him off from his army encamped about Sens and Langres. With all secrecy he went to Vienna, and thence, attended by only a few horsemen, through the territory of the Haedui to his troops. The hopes, which had induced the conspirators to declare themselves, vanished; peace continued in Italy, and Caesar stood once more at the head of his army.
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Reference address : https://www.ellopos.net/elpenor/rome/5-07-subjugation-west.asp?pg=111