Sulla was campaigning in Greece and Macedon fighting against the forces of king Mithridates of Pontus (see: First Mithridatic War).
[1] Flaccus probably employed experienced troops, drawing his recruits from veterans of the recent Social War, but due to a lack of funds he was only able to raise two legions.
[3] After failing to capture Mithridates, Fimbria allowed his troops to pillage several cities, most prominently razing Ilium to the ground.
Archelaus convinced Lucius Licinius Murena, the Roman general tasked with protecting Bithynia, that Mithridates was planning another war with Rome.
Lucullus, whom Sulla had left in charge of Asia province, launched an attack on the city, defeating Mytilene’s forces in a pitched battle before its walls.
Landing at an unspecified location in Asia, he assumed command of the local Roman forces including the Fimbrians.
[8] Lucullus had planned to invade Pontus before going after Mithridates himself, but he received word that his colleague, the proconsul Marcus Aurelius Cotta, had been defeated in battle and was now under siege in Chalcedon.
Similarly, Mithridates was reluctant to risk battle against the capable Lucullus, who eventually managed to trap the king's army on the Cyzicus Peninsula in a counter-siege.
Unable to beat Lucullus in open battle, Tigranes and Mithridates began resorting to hit-and-run tactics.
[11] They stayed on garrison duty in Pontus, where they were caught off guard by Mithridates when he suddenly returned to his kingdom in 67 BC at the head of a combined Armenian-Pontic army.
[12] It is unclear whether the Fimbrians fought at the disastrous Battle of Zela that year, but their continued existence as two legions in 66 BC suggests that they probably did not.
Ultimately, Lucullus extracted from his army a promise to protect Rome's remaining possessions in the East—but their days of campaigning under him were at an end.
[15] In Pontus Pompey caught up with and defeated Mithridates' army at the Battle of the Lycus, but the Pontic king escaped yet again.
Before he advanced into Armenia, Pompey reduced the numbers of his army and granted some of his long-serving soldiers (almost certainly including the Fimbrians) their discharge, settling them in a new city called Nicopolis.