The key event in Rome that led to the downfall of the Roman Republic and the emergence of the Empire was the Assassination of Julius Caesar in 44 B.C. His murder, orchestrated by a group of senators, was motivated by fears of his growing power and potential kingship. This pivotal moment triggered a series of civil wars, leading to the rise of Augustus Caesar and the establishment of the Roman Empire. The conflict fundamentally altered the political landscape of Rome, transitioning from a republic characterized by senatorial rule to an autocratic empire, fundamentally changing governance and the concept of power in the ancient world.