The downfall of the Roman Republic was a complex series of events influenced by various political, social, and military factors. Key events include the expansion of the Republic leading to increased wealth and social inequality, which fueled class tensions. Political corruption and power struggles, particularly between prominent figures like Julius Caesar, Pompey, and Crassus, destabilized governance. The crossing of the Rubicon by Caesar in 49 BC signaled a civil war that further dismantled the Republic's structure. Ultimately, the assassination of Caesar in 44 BC and the subsequent rise of Augustus marked the end of the Republic and the beginning of the Roman Empire.