When the Social War had broken out, Rome was fully occupied with its own affairs. Mithridates VI, king of Pontus, used Rome's preoccupation to invade the province of Asia. Half of the province of Achaea (Greece), Athens taking the lead, rose against its Roman rulers, supported by Mithridates.
When Sulla arrived at Athens, the city's fortifications proved too much for him to charge. Instead he starved them out, whilst his lieutenant, Lucius Lucullus, raised a fleet to force Mithridates out of the Aegean Sea.
Early in 86 BC Athens fell to the Romans.
Though Archelaus, the ablest general of Mithridates, now threatened with a large army from Thessaly. Sulla marched against him with a force only a sixth in size and shattered his army at Chaeronea.
A Roman consul, Valerius Flaccus, now landed with fresh forces in Epirus, to relieve Sulla of his command. But Sulla had no intention of relinquishing his power. News reached him that general Archelaus had landed another huge force. Immediately he turned southwards and destroyed this force at Orchomenus.
Meanwhile Flaccus, avoiding a conflict with Sulla, headed toward Asia seeking to engage Mithridates himself. Though he never reached it. His second-in-command, C. Flavius Fimbria, led a mutiny against him, killed him and assumed command himself. Fimbria crossed the straights and started operations in Asia.
Meanwhile Sulla opened negotiations with the defeated Archelaus. An conference was arranged in 85 BC between Sulla and Mithridates and a treaty was struck by which Mithridates was to surrender his conquests to Rome and retreat behind the borders he'd held before the war. So too, was Pontus to hand over a fleet of seventy ships and pay a tribute.
It now remained to settle the problem of Fimbria, who could only hope to excuse his mutiny with some success. With the war over and Sulla closing on him with his troops, his situation was hopeless. Alas, his troops deserted him and Fimbria committed suicide.
Therefore, in 84 BC, his campaigns a total success, Sulla could start making his was back to Rome.