It was not long before men appeared  who were able to destroy the Senate's power over the army. The first was named Gaius Marius (d. 87 BC). Marius was not really a reformer, but he was unpopular with the Senate because he did not come from a distinguished noble family. Normally, he would not have had a chance to reach high office, but he was able to get enough support from the equestrians to win the office of Consul in 107 BC. Once in office, Marius made important changes in the way the soldiers were recruited for military service. Previously soldiers had been drafted from among the Romans who owned land or other property. But by 107, the number of Roman farmers had declined, leaving few citizens available for military service. So Marius decided to seek volunteer soldiers from among the urban poor and unemployed. He promised to work for bonuses of land and money for the soldiers after they had finished their service. In this way, he got many men to volunteer. These promises helped him as well. In order to make good on his promises he would need support from the assembly. So the soldiers supported him in politics, in order to would receive their bonuses. Thus Marius was able to be elected consul five times (104 -100) . Because the men who made up the Roman army under Marius looked to him rather than to the Senate for their support, this new Roman army was more loyal to Marius, their leader, than they were to the Roman state. From this time on, Roman armies were often more loyal to their generals than they were to the Senate or to the Roman state as a whole.

Thus, Marius made the army a force in politics which it had not been before. It was not long before someone got the idea of using that force to threaten the government itself. That man was Cornelius Sulla (d. 78 B.C.). Sulla was a Roman from a good family who supported the nobiles in politics. In 88 BC he was made general (a proconsul) to lead a large army to a war in Asia. But after he departed from the city with his troops, the anti-Senatorial, pro-Marian leaders were able to remove him from his command. But Sulla still had a large army behind him, so he asked them to help him seize control of the government — and they did. Sulla marched his army into the city of Rome. He retook the government, killed his enemies, then he went East and fought his war.

After the war in the East was over, Sulla had to return to Rome and fight another civil war to regain control of the state again. He defeated his enemies, and made himself dictator for two years. During that period he made many new laws to strengthen the power of the Senate in the government. None of these laws lasted for a very long time, but Sulla was important in other ways. He was the first general to turn his army against the government and Rome. Whereas Marius had merely asked his troops to vote for him, Sulla showed that a general might use his support from the Army in a military way – to seize the reins of power illegally.

In the years between 200 and 79 B.C., the Roman republican government of magistrates, Assembly and Senate rapidly declined and moved toward final destruction. The Senate had to take a large part of the blame for this development. They were much too arrogant and selfish to solve any of the social and economic problems confronting Rome. Indeed, the Senate opposed reform of any kind with great tenacity. The Roman constitution was organized in a way which made reform possible. It was possible, for instance, for the Gracchi brothers to secure reform without the help, and even against the opposition of the Senate. But change was difficult, because the powerful and prestigious Senate opposed change. For primarily self-serving reasons the Senate was willing to resort to illegal means to stop any reform. The result was that no one was particularly concerned with legality anymore. Both reformers and conservatives began to think that any means could and should be employed to gain their ends. Violence became more and more a feature of Roman politics. The most ominous development was the growth of the army as a force in politics with goals and interests of its own. After Sulla's time, any successful general became a potential threat to the Roman state. And that is exactly what would happen.

The first really powerful military leader after Sulla was a man named Pompey the Great (d.48 B.C.). He had been a subordinate of Sulla. In the 70's and 60's Pompey was Consul once, and he also held several important governorships in the provinces. The Senate did not like him very much, however, because he didn’t come from a noble family. But Pompey was very popular with a lower classes, and in his military commands he was able to win the support of a large number of soldiers.

At several points before 60 BC, Pompey might have seized control of the government but he really did not wish to do that. Pompey always hoped that he could win the support and approval of the Senators, so he refused to take the final step toward dictatorship. Unfortunately for Pompey, the Senators always refused to cooperate with him because of his ambition, and they were also jealous of his military successes. In 61 B.C., after a very successful naval campaign in the eastern Mediterranean, Pompey’s luck with the Senate ran out. Fearful of his ambition and auctoritas, the Senate refused to reward his soldiers, give contracts to his equestrian supporters, or even confirm his diplomatic agreements with Eastern rulers.

Pompey needed to find allies. He especially needed consul to support him in the Senate. To get a consul elected Pompey would need a great deal of money and patronage in high places. So he hit upon a scheme to get what he wanted. For money and patronage Pompey made an alliance with an old adversary, Marcus Licinius Crassus. Crassus was the richest man in Rome and recently had fallen into disfavor with the Senate leaders as well. Crassus wanted contracts for his equestrian clients and the glory of a great military command, and he was willing to pay for both. What Pompey and Crassus needed was a consular candidate who had the personal and family prestige to win and be a powerful political influence. This man was Gaius Julius Caesar (d.44 B.C.). Caesar was a political opportunist from a very distinguished Roman family that had fallen upon hard times politically. Caesar was ambitious, wanting not only to increase his own power and prestige, but also to restore his family to the position that it had held earlier in the Republic. The three formed what has come to be called the First Triumvirate.

Caesar was elected Consul and helped Pompey to get the bonuses for his soldiers. In return for this service, Caesar was received the proconsulship of Roman Gaul in southern France. He served there for nine years from 58 to 50 BC. Caesar's career in Gaul shows the dangers inherent in a lack of control that the Romans had over their governors.

Caesar provoked a series of wars with the barbarian tribes on the borders of his province, and he eventually took over all of France up to the borders of the Rhine River. In the process he was able to build up a huge army that was fiercely loyal to him. So great did his power become that Pompey and the Senate were forced to ally with one another against Caesar. In 49 BC, the Senate tried to remove Caesar from his governorship. He refused to step down; in fact he took his army and marched on Rome. This began a civil war that continued from 49 to 45 BC. In the war, Pompey was killed along with many leaders of the Senate. By 45, Caesar was master of the entire Roman state.

Caesar had himself made dictator for life and he probably would make Rome a monarchy with himself as king. He was certainly a position to do so, for most of his opponents were dead, and he had the support of the army. But before he could proceed very far, he was assassinated, in 44 BC, by a small group of nobiles whose lives he had spared after the war.

With Caesar dead, the various other leaders struggled to regain the place which he had held. There were two more civil wars between 44 and 30 BC. By 30 BC, one man had emerged as dominant. He was the nephew of Caesar was known as Octavian. He would become Caesar Augustus.