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 In a dispute over the command of the war against Mithridates, initially awarded to Sulla by the Senate, but withdrawn as a result of Marius' intrigues, Sulla marched on Rome in an unprecedented act and defeated Marian forces in battle.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 Battle of the Colline Gate. He then revived the office of dictator, which had been inactive since the Second Punic War, over a century before. He used his powers to purge his opponents, and reform Roman constitutional laws, to restore the primacy of the Senate and limit the power of the tribunes of the plebs. Resigning his dictatorship in 79 BC, Sulla retired to private life and died the following year.