Short answers, pulled from the story.
The traditional date for the overthrow of the Roman monarchy is c. 509 BC, derived from the Varronian chronology compiled by Marcus Terentius Varro during the late republic. However, other ancient sources suggest dates ranging from 508 to 507 BC, and some modern scholars argue the republic may have emerged as late as 472 or 450 BC.
According to the traditional account, the uprising was led by Lucius Junius Brutus, the king's nephew, alongside Lucius Tarquinius Collatinus, Spurius Lucretius Tricipitinus, and Publius Valerius Poplicola. Brutus and Collatinus became the first consuls of the Roman Republic, though the title used in that earliest period was praetor.
The traditional account says the rape of the noblewoman Lucretia by Sextus Tarquinius, the king's second son, provoked the uprising. After revealing the assault to a group of noblemen, Lucretia killed herself, and the resulting outrage led to the expulsion of King Lucius Tarquinius Superbus and his family.
The historian James Richardson argues that Lucius Junius Brutus never existed. T. P. Wiseman and other critical scholars believe many of the characters in the traditional story were ahistorical inventions created in the fourth and third centuries BC by Roman families wishing to embellish their ancestral histories.
Lars Porsenna, king of Clusium, attacked Rome on Tarquin's behalf after the expulsion. Some ancient accounts say he was stopped at the bridge by Horatius Cocles; others indicate he successfully captured Rome and imposed harsh peace terms. A separate Greek historical tradition, cited by Dionysius of Halicarnassus, records that Porsenna's forces were decisively defeated at the Battle of Aricia in 504 BC.
During the French Revolution, Lucius Junius Brutus was adopted as a symbol of civic republican virtue. Boys and whole towns were named Brutus. Voltaire's play Brutus, written c. 1730 but initially unsuccessful, became enormously popular in the 1790s after the abolition of the French monarchy and the establishment of a republic.