The Gracchi Brothers tried to limit the amount of conquered land people could own. However, this was unsuccessful. Member of the wealthy ruling classes considered them dangerous radicals so they killed them. They showed thats Rome's government might not work on a large empire.
In 87 B.C.E. Marius marched on Rome, and placed the city under military occupation. When Marius died Sulla Sulla took his place. In 83 B.C.E. he seized Rome and killed people he did not like. But he ignored Rome's social problem, which left a lasting impact.
Rome fell into civil war during the first century B.C.E. This was largely due to the rule of Marius and Sulla. During the civil war Rome's social problems went neglected and this caused spikes of social eruptions.
Sulla seized Rome in 83 B.C.E. He immediately started a grisly slaughter on his enemies. At the time of his death he had killed and supported the killing of thousands of people. He did not care about Rome's actual problems and this hurt Rome in the long term.
Julius Caesar favored liberal policies and social reform. After some strong military wins he earned respect and declared himself dictator for life. During this time he centralized military and political functions, he distributed property among everyone, he supported building projects, and opened up Roman citizenship.
Octavian was Caesars grand nephew. In a naval battle he defeated rival Mark Antony. He than became Augustus which means strong religious connotations