Rome's first Civil War began as the result of conflict between
two powerful political and military leaders in Rome: Gaius Marius and Lucius Cornelius Sulla. The conflict arose primarily due to a power struggle and differing ambitions.
Gaius Marius was a popular general who had gained fame for his military successes against the Germanic tribes in the late 2nd century BCE. He was a supporter of the populares, a political faction that championed the rights of the common people and sought to limit the power of the aristocracy. Marius aimed to strengthen the position of the plebeians (commoners) and provide them with more political opportunities.
Lucius Cornelius Sulla, on the other hand, was also a prominent military leader. He had fought alongside Marius in various campaigns, including the war against the Germanic tribes. However, Sulla belonged to the optimates, a faction that represented the interests of the aristocracy and the Senate. Sulla sought to maintain the power and privileges of the patricians (aristocrats) and the Senate.
Conflict between Marius and Sulla intensified when both leaders vied for command of the Roman army in the war against Mithridates VI of Pontus, a powerful king in Asia Minor. The Senate initially appointed Sulla to lead the campaign, but Marius, using his popular support and political connections, managed to seize command for himself.
Infuriated, Sulla marched his legions back to Rome, leading to violent clashes in the city between the supporters of Marius and Sulla. At first, Sulla was forced to flee Rome, but he soon returned with his armies and managed to gain control of the city, forcing Marius and his allies to flee.
This marked the beginning of Rome's first Civil War in 88 BCE. The conflict would continue for several years as both leaders fought for control over Rome and its territories. The war only ended in 82 BCE, when Sulla emerged victorious and established himself as a dictator, implementing a series of political reforms aimed at restoring power to the aristocracy.