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
A firmer hand now grasped the reins, and put an end to the pitiful
vacillation. In the autumn of 473 Milo, the general of Pyrrhus,
landed with 3000 Epirots and occupied the citadel of the town.
He was followed in the beginning of the year 474 by the king himself,
who landed after a stormy passage in which many lives were lost.
He transported to Tarentum a respectable but miscellaneous army,
consisting partly of the household troops, Molossians, Thesprotians,
Chaonians, and Ambraciots; partly of the Macedonian infantry and the
Thessalian cavalry, which Ptolemy king of Macedonia had conformably to
stipulation handed over to him; partly of Aetolian, Acarnanian, and
Athamanian mercenaries.
Altogether it numbered 20,000 phalangitae,
2000 archers, 500 slingers, 3000 cavalry, and 20 elephants, and thus
was not much smaller than the army with which fifty years before
Alexander had crossed the Hellespont.