And it wasn't that Sulla and Marius had been enemies since they were born. Sulla had served under marius in several wars, and they gained successes together. Where Marius was the general in fight against numidians and teutones, Sulla served in his staff. It was not until later that these great men in the history of Rome came to stand on opposite sides. When sulla was given the command for the first Mithridatic War, Marius tried to get via clever machinations in the senate to get control himself, and succeeded in this.
The result was that Sulla marched on Rome to revert this decision. He exiled Marius and many supporters and made sure he placed Rome in the hands of consuls he could trust. Lucius Cornelius Cinna and Gnaeus Octavius were left in control, while Sulla would face the threat of Mithridates in the east.
However, it soon became clear that Cinna had political ideas which had much in common with Marius, and when Cinna got into trouble in the senate, he made the logical alliance. Sulla wasn't that popular for being the first who marched on Rome, while Marius had done great things for the republic and was considered a hero. By force, Cinna got Marius back into Rome. When entering the city, Marius showed how ruthless a general and polician has to be. He ordered many of his political opponents to be killed and literally cut down much of the support that Sulla still had.
That left the republic in an odd situation. Marius and Cinna might be in power in Rome, but Sulla had shown he was able to do the unthinkable and use his legions to force Rome, and he was still out there. At the moment he was still occupied with Mithridates, but after that war had finished, what would happen then?
Fenchurch
Cogito Ergo Sum
VitaminR
kiwieagle
Faraday, Gnaeus Papirius Carbo,
Fishythefish, Lucius Cornelius Scipio Asiaticus,
Ellibereth, Gaius Julius Ceasar,