Why did the roman monarchy fall?

When the Etruscan rule weakened, the Romans rebelled, driving the Etruscan kings out of Rome. After the expulsion of the Etruscans, the monarchy became a republic.

The Overthrow of the Roman monarchy was a political revolution in ancient Rome in around 509 BC, which resulted in the expulsion of the last king of Rome, Lucius Tarquinius Superbus, and the establishment of the Roman Republic.