 Complete the following phrase:  Sulla played an important role in the long political struggle between the optimates and populares factions at Rome. He was a leader of the former, which sought to maintain the senatorial supremacy against the populist reforms advocated by the latter, headed by Marius. In a dispute over the command of the war against Mithridates, initially awarded to Sulla by the Senate, but withdrawn as a result of Marius intrigues, Sulla marched on Rome in an unprecedented act and defeated Marian forces in battle. The populares nonetheless seized power once he left with his army to Asia. He returned victorious from the east in 82 BC, marched a second time on Rome, and crushed the populares and their Italian allies at the 