The populares and the optimates

In 118 BC, King Micipsa of Numidia (current-day Algeria and Tunisia) died. He was survived by two legitimate sons, Adherbal and Hiempsal, and an illegitimate son, Jugurtha. Micipsa divided his kingdom between these three sons. Jugurtha, however, turned on his brothers, killing Hiempsal and driving Adherbal out of Numidia. Adherbal fled to Rome for assistance, and initially Rome mediated a division of the country between the two brothers. Eventually, Jugurtha renewed his offensive, leading to a long and inconclusive war with Rome. He also bribed several Roman commanders, and at least two tribunes, before and during the war. His nemesis, Gaius Marius, a legate from a virtually unknown provincial family, returned from the war in Numidia and was elected consul in 107 BC over the objections of the aristocratic senators. Marius invaded Numidia and brought the war to a quick end, capturing Jugurtha in the process. The apparent incompetence of the Senate, and the brilliance of Marius, had been put on full display.[56] The populares party took full advantage of this opportunity by allying itself with Marius. Several years later, in 88 BC, a Roman army was sent to put down an emerging Asian power, king Mithridates of Pontus. The army, however, was defeated. One of Marius' old quaestors, Lucius Cornelius Sulla, had been elected consul for the year, and was ordered by the senate to assume command of the war

against Mithridates. Marius, a member of the "populares" party, had a tribune revoke Sulla's command of the war against Mithridates. Sulla, a member of the aristocratic ("optimates") party, brought his army back to Italy and marched on Rome. Sulla was so angry at Marius' tribune that he passed a law intended to permanently weaken the tribunate.[57] He then returned to his war against Mithridates. With Sulla gone, the populares under Marius and Lucius Cornelius Cinna soon took control of the city. During the period in which the populares party controlled the city, they flouted convention by re-electing Marius consul several times without observing the customary ten year interval between offices.[citation needed] They also transgressed the established oligarchy by advancing unelected individuals to magisterial office, and by substituting magisterial edicts for popular legislation. Sulla soon made peace with Mithridates. In 83 BC, he returned to Rome, overcame all resistance, and recaptured the city. Sulla and his supporters then slaughtered most of Marius' supporters. Sulla, having observed the violent results of radical popular reforms, was naturally conservative. As such, he sought to strengthen the aristocracy, and by extension the senate.[58] Sulla made himself dictator, passed a series of constitutional reforms, resigned the dictatorship, and served one last term as consul. He died in 78 BC.