The prophecy now hastened to its fulfilment. As the army lay before the town of Ardea, belonging to the Rutulians, south of Rome, a dispute arose among the sons of the king and their cousin Collatinus, as to which had the most virtuous wife. There being nothing to keep them in camp, the young men arose from their cups and rode to Rome, where they found the princesses at a banquet revelling amid flowers and wine. Lucretia, the wife of Collatinus, was found at Collatia among her maidens spinning, like the industrious wife described in the Proverbs. The evil passions of Sextus were aroused by the beauty of his cousin's wife, and he soon found an excuse to return to the home of Collatinus. He was hospitably entertained by Lucretia, who did not suspect the demon that he was, and one night he entered her apartment and with vile threats overcame her. In her terrible distress, Lucretia sent immediately for her father, Lucretius, and her husband, Collatinus. They came, each bringing a friend, Brutus being the companion of the outraged husband. To them, with bitter tears, Lucretia, clad in the garments of mourning and almost beside herself with sorrow, told the story of crime, and, saying that she could not survive dishonor, plunged a knife into her bosom and fell in the agony of shame and death!

At this juncture Brutus threw off the assumed stupidity that had veiled the strength of his spirit, and taking up the reeking knife, exclaimed: "By this blood most pure, I swear, and I call you, O gods, to witness my oath, that I shall pursue Lucius Tarquin the Proud, his wicked wife, and all the race, with fire and sword, nor shall I permit them or any other to reign in Rome!" So saying, the knife was handed to each of the others in turn, and they all took the same oath to revenge the innocent blood. The body of Lucretia was laid in the forum of Collatia, her home, and the populace, maddened by the sight, were easily persuaded to rise against the tyrant. A multitude was collected, and the march began to Rome, where a like excitement was stirred up; a gathering at the forum was addressed by Brutus, who recalled to memory not only the story of Lucretia's wrongs, but also the horrid murder of Servius, and the blood-thirstiness of Tullia. On the Campus Martius the citizens met and decreed that the dignity of king should be forever abolished and the Tarquins banished. Tullia fled, followed by the curses of men and women; Sextus found his way to Gabii, where he was slain; and the tyrant himself took refuge in Cære, a city of Etruria, the country of his father.

There is a tradition that it had been the intention of Servius to resign the kingly honor, and to institute in its stead the office of Consul, to be jointly held by two persons chosen annually. There seems to be some ground for this belief, because immediately after the banishment of the Tarquins, the republic was established with two consuls at its head. [Footnote: The custom of confiding the chief civil authority and the command of the army to two magistrates who were changed each year, was not given up as long as the republic endured, but towards its end, Cinna maintained himself in the office alone for almost a year, and Pompey was appointed sole consul to keep him from becoming dictator. The authority of consul was usurped by both Cinna and Marius. The consuls were elected by the comitia of the centuries. They could not appear in public without the protection of twelve lictors, who bore bundles of twigs (fasces) and walked in single file before their chiefs.] The first to hold the highest office were Lucius Junius Brutus and Lucius Tarquinius Collatinus, husband of Lucretia.

Some time after Tarquin had fled to Cære, he found an asylum at Tarquinii, and from that city made an effort to stir up a conspiracy in his favor at Rome. He sent messengers ostensibly to plead for the restoration of his property, but really for the purpose of exciting treason. There were at Rome vicious persons who regretted that they were obliged to return to regular ways, and there were patricians who disliked to see the plebeians again enjoying their rights. Some of these were ready to take up the cause of the deposed tyrant. The conspirators met for consultation in one of the dark chambers of a Roman house, and their conference was overheard. They were brought before the consuls in the Comitium, and, to the dismay of Brutus, two of his own sons were found among the number. With the unswerving virtue of a Roman or a Spartan, he condemned them to death, and they were executed before his eyes. The discovery of the plot of Tarquin put an end to his efforts to regain any foothold at Rome by peaceable methods, and he made the appeal to arms. These plots led to the banishment of the whole Tarquinian house, even the consul whose troubles had brought the result about being obliged to lay down his office and leave the city. Publius Valerius was appointed in his stead. For a time he was in office alone, and several times he was re-chosen. He was afterwards known as Poplicola, "the people's friend," on account of certain laws that he passed, limiting the power of the aristocrats and alleviating the condition of the plebeians. [Footnote: When Valerius was consul alone he began to build a house for himself on the Velian Hill, and a cry was raised that he intended to make himself king, upon which he stopped building. The people were ashamed of their conduct and granted him land to build on. One of his laws enacted that whoever should attempt to make himself king should be devoted to the gods, and that any one might kill him. When Valerius died he was mourned by the matrons for ten months. See Plutarch, Poplicola.]