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
Sulla sent to Spain Gaius Annius and Gaius Valerius Flaccus,
the former as governor of Further Spain, the latter as governor
of the province of the Ebro. They were spared the difficult task
of opening up the passes of the Pyrenees by force, in consequence
of the general who was sent thither by Sertorius having been killed
by one of his officers and his troops having thereafter melted away.
Sertorius, much too weak to maintain an equal struggle, hastily
collected the nearest divisions and embarked at New Carthage--for
what destination he knew not himself, perhaps for the coast of
Africa, or for the Canary Islands--it mattered little whither,
provided only Sulla's arm did not reach him. Spain then willingly
submitted to the Sullan magistrates (about 673) and Flaccus fought
successfully with the Celts, through whose territory he marched,
and with the Spanish Celtiberians (674).