Answer:
509 BC: The creation of the Roman Republic. As with the foundation of the city, later Romans believed they knew the precise date of the beginning of the Republic: 509 BC, when the seventh and last king of Rome, the tyrannical Tarquinius Superbus, was thought to have been ousted by an aristocratic coup. Although sources for the early Republic are better than those for the preceding regal period, the veracity of this tale is also in doubt.
Step-by-step explanation:
In 509 BC, King Lucius Tarquinius Superbus was overthrown by the noble men of Rome. The king of Clusium, Lars Porsenna, sieged Rome. The city signed a treaty of support with Carthage, the temple of Jupiter Capitolinus was consecrated and a new office, called consul, was created.