Based on the orders of Marius, some of his soldiers went through Rome killing the leading supporters of Sulla, including Octavius.
Having managed this achievement, the Marians sent out Lucius Valerius Flaccus with an army to relieve Sulla of his command in the east.
According to Plutarch's biography on Sulla, Gaius Flavius Fimbra eventually agitated against his commanding officer and incited the troops to murder Flaccus in 84 BC.
Many deserted to Sulla before Flaccus had arranged to pack up and move on to north, to threaten Mithridates’ northern dominions.
With Mithridates defeated for the moment and Cinna now dead as a result of a mutiny in Ancona, Sulla was determined to regain control of Rome from his enemies.
[4] As soon as he had set foot in Italy, the outlawed nobles and old Sullan supporters who had survived the Marian-Cinna regime flocked to his banner.
The most prominent among them were Quintus Caecilius Metellus Pius, Marcus Licinius Crassus, and Lucius Marcius Philippus.
[9] Scipio was unwilling to risk a battle with his opponent's battle-hardened army and welcomed Sulla's offer to negotiate.
The Consul and his son were found cowering in their tents and brought to Sulla, who released them after extracting a promise that they would never again fight against him or rejoin Carbo.
Norbanus, however, escaped back to Rome and had Metellus Pius and all other senators marching with Sulla declared enemies of the state.
[11] At the end of the campaigning season of 83 BC, Marcus Lucullus, one of Sulla's legates, defeated a numerically superior force (50 cohorts to his 16) at Fidentia.
Quintus Sertorius levied men in Etruria, old veterans of Marius came out of retirement to fight under his son, and the Samnites gathered their warriors in support of Carbo, hoping to destroy Sulla, the man who defeated them in the Social War.
[14] As the campaigning season opened, Sulla advanced along the Via Latina towards the capital and Metellus supported by Pompey led Sullan forces into northern Italy.
[15] Marius the Younger marched his army south-east into Campania and met Sulla's forces at Sacriportus (near Signia).
While Sulla's men were preparing the camp (digging a ditch, throwing up earthworks) Marius suddenly attacked.
Sulla's veterans simply stuck their pila into the ground to create a makeshift barricade and drew their swords.
Marius' force were put on the defensive, their left began to waver and five cohorts of foot soldiers and two of horse deserted to Sulla.
[17] Upon his defeat Marius sent word to the praetor Lucius Junius Brutus Damasippus in Rome, to kill any remaining Sullan sympathisers left before Sulla could take the city.
Upon hearing that Marius the Younger had been defeated at Sacriportus, Carbo withdrew to Ariminum, severely harassed by cavalry attacks on his rearguard by Pompey.
[25] Having taken and looted the town of Sena, Crassus and Pompey severely defeated Carrinas who had marched against them, killing 3,000 Marian soldiers and forcing him to seek refuge in Spoletium.
Their commander, a man called Albinovanus, hatched a plan with the Sullans to assassinate Norbanus and his senior officers (to show his good faith).
[35] The survivors of the Marian cause were given refuge on Sicily by Marcus Perperna, in Africa by Domitius Ahenobarbus and in Spain by Quintus Sertorius.
[37] Sulla sent Gaius Annius Luscus with several legions to take the Spanish provinces from Quintus Sertorius.
In total control of Rome and Italy, Sulla instituted a series of proscriptions (a program of executing those whom he perceived as enemies of the state and confiscating their property).
[39]The proscriptions are widely perceived as a response to similar killings which Marius and Cinna had implemented while they controlled the Republic during Sulla's absence.
Proscribing or outlawing every one of those whom he perceived to have acted against the best interests of the Republic while he was in the East, Sulla ordered some 1,500 nobles (i.e., senators and equites) executed, although it is estimated that as many as 9,000 people were killed.
[45] Sulla also codified, and thus established definitively, the cursus honorum,[45] which required an individual to reach a certain age and level of experience before running for any particular office.
[45] Finally, in a demonstration of his absolute power, Sulla expanded the "Pomerium", the sacred boundary of Rome, unchanged since the time of the kings.
Near the end of 81 BC, Sulla, true to his traditionalist sentiments, resigned his dictatorship, disbanded his legions and re-established normal consular government.
[47][48] In a manner that the historian Suetonius thought arrogant, Julius Caesar would later mock Sulla for resigning the dictatorship.