A Roman army is sent in 88 BCE to put down the emerging Asian power, Mithridates IV of Pontus, is defeated.
Sulla, forming important alliances by his marriage—his fourth—to Caecilia Metella in this year, initially receives command of the war against Mithridates, but Gaius Marius, although now an old man, still wants to lead the Roman armies.
Before leaving for the East, Sulla and his colleague Quintus Pompeius Rufus block legislation of the tribune Publius Sulpicius Rufus to ensure the rapid organization of the Italian allies within the Roman citizenship.
When Sulpicius finds an ally in Marius who will support the bill, he has his supporters riot.
Sulla returns to Rome from the siege at Nola to meet with Pompeius Rufus; however, Sulpicius' followers attack the meeting, forcing Sulla to take refuge in Marius' house, who then forces him to support Sulpicius' pro-Italian legislation.
Sulla's own son-in-law is killed in these riots.
After Sulla leaves Rome again for Nola, Sulpicius (after receiving a promise from Marius to wipe out his enormous debts) calls an assembly to reverse the Senate's decision on Sulla's command, transferring it to Marius.
Sulpicius also uses the assemblies to eject Senators from the Roman Senate until there are not enough senators to form a quorum.
Violence in the Forum ensues, some nobles try to lynch Sulpicius (as had been done to the brothers Gracchi, and to Saturninus) but fail in the face of his bodyguard of gladiators.
Sulla receives news of this at the camp of his victorious Social War veterans, waiting in the south of Italy to cross to Greece.
He announces the measures that had been taken against him, and his soldiers stone the envoys of the assemblies who come to announce that the command of the Mithridatic War had been transferred to Marius.
Sulla then takes six of his most loyal legions and marches on Rome.
This is an unprecedented event.
No general before him had ever crossed the city limits, the pomoerium, with his army.
Most of his commanders (with the exception of his kinsman through marriage Lucullus) refuse to accompany him.
Sulla justifies his actions on the grounds that the Senate had been neutered and the mos maiorum ("the way of the elders"/"the traditional way", which amounts to a Roman constitution though none of it is codified as such) had been offended by the Senate's negation of the rights of the year's consuls to fight the year's wars.
Armed gladiators are unable to resist organized Roman soldiers; and although Marius offers freedom to any slave that will fight with him against Sulla (an offer which Plutarch says only three slaves accepted), he and his followers are forced to flee the city, eventually to Africa.
Sulla consolidates his position, declares Marius and his allies hostes (enemies of the state), and addresses the Senate in harsh tones, portraying himself as a victim, presumably to justify his violent entrance into the city.
After restructuring the city's politics and strengthening the Senate's power, Sulla returns to his camp and proceeds with the original plan of fighting Mithridates in Pontus, setting off for Greece.
