Rape of Lucretia
The story as told by Livy 
In the time of king Tarquinius Superbus, the Romans were laying siege to Ardea, in the territory of the Rutulians. One day, some of the young leaders of the Roman army were boasting about the virtues of their wives, each claiming to have the best. They decided to ride their horses to secretly observe their wives. In Rome they saw that the daughters-in-law of the king were enjoying a lavish dinner-party. In Collatia, however, Lucretia, wife of Collatinus Tarquinius, (son of Egerius), was up in the middle of the night with her servants, working wool. Collatinus and the others were welcomed into the house, among them Sextus Tarquinius, son of the king.
A few days later, Sextus Tarquinius secretly returned to the house of Collatinus Tarquinius, where he was given dinner and lodging by Lucretia. Late at night, the prince entered Lucretia's room, and attempted to rape her. She resisted until he threateded to kill both her and a slave, and make it seem that she had been killed when caught in an act of audultery. Rather than leave this legacy of dishonor for her husband, she relented.
As soon as Sextus Tarquinius had left, Lucretia sent urgent messages to her father, Spurius Lucretius, and to her husband, telling them to come to her in haste, as a terrible thing had happened. Her father came with Publius Valerius and her husband arrived with Lucius Junius Brutus. Lucretia tearfully told what had happened and asked each of the men to seek revenge. The men tried to console her, calling her blameless, as force had been used. She, however, prefered death to even a hint of dishonor and, pulling a dagger from her clothes, took her own life.
In the first moment of grief and shock, Brutus pulled out the bloody dagger and swore to avenge Lucretia and all others who had been wronged by the king, stopping at nothing short of the expulsion of the king from Rome. Collatinus, Lucretius and Valerius joined in his oath and then they carried the body of Lucretia to the forum. There, the words and passion of these men inflamed a band to march to Rome. Collatia was garrisoned and the armed band left for Rome, led by Brutus.
In Rome, some of the leading men joined the band and there Brutus again spoke of the terrible crime commited by prince, and all the other outrages suffered by the people under king Tarquinius Superbus. The people decided to expel the king and banish his family. A band led by Brutus was sent to the army at Ardea, to take control in place of the king; Lucretius, who had already been appointed prefect, was left in command in Rome.
When news reached the king in Ardea, he left for Rome, but the gates were closed against him. He went into exile in Caere in Etruria with some of his family. Sextus Tarquinius was killed by some of his old enemies. In this way the reign of kings was brought to an end in Rome.