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
So long as Domitius hoped for the arrival of Pompeius, he caused the town to be defended; when the letters of Pompeius had at length undeceived him, he resolved, not forsooth to persevere at the forlorn post-- by which he would have rendered the greatest service to his party-- nor even to capitulate, but, while the common soldiers were informed that relief was close at hand, to make his own escape along with his officers of quality during the next night. Yet he had not the judgment to carry into effect even this pretty scheme.
The confusion of his behaviour betrayed him. A part of the men began to mutiny; the Marsian recruits, who held such an infamy on the part of their general to be impossible, wished to fight against the mutineers; but they too were obliged reluctantly to believe the truth of the accusation, whereupon the whole garrison arrested their staff and handed it, themselves, and the town over to Caesar (20 Feb.). The corps in Alba, 3000 strong, and 1500 recruits assembled in Tarracina thereupon laid down their arms, as soon as Caesar's patrols of horsemen appeared; a third division in Sulmo of 3500 men had been previously compelled to surrender.
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Reference address : https://www.ellopos.net/elpenor/rome/5-10-brundisium-pharsalus-thapsus.asp?pg=24