The Roman Kingdom (Latin: Regnum Romanum) was the monarchical government of the city of Rome and its territories. Little is certain about the history of the Roman Kingdom, as no written records from that time survive, and the histories about it were written during the Republic and Empire and are largely based on legend. However, the history of the Roman Kingdom began with the city's founding, traditionally dated to 753 BC, and ended with the overthrow of the kings and the establishment of the Republic in about 509 BC. Romulus was Rome's first king and the city's founder. In 753 B.C., Romulus began building the city upon the Palatine Hill. After founding Rome, he permitted men of all classes to come to Rome as citizens, including slaves and freemen without distinction. After the death of Romulus there was an interregnum for one year, during which ten men chosen from the senate governed Rome as successive interreges. Numa Pompilius The second king, a Sabine, was eventually chosen by the senate to succeed Romulus, on account of his reputation for justice and piety. Tullus Hostilius the third king was much like Romulus in his warlike behavior and completely unlike Numa in his lack of respect for the gods. Tullus waged war against Alba Longa, Fidenae and Veii and the Sabines. It was during Tullus' reign that the city of Alba Longa was completely destroyed and Tullus integrated its population into Rome. Following the mysterious death of Tullus, the Romans elected a peaceful and religious king in his place, Numa’s grandson, Ancus Marcius. Much like his grandfather, Ancus did little to expand the borders of Rome and only fought war when his territories needed defending. He also built Rome's first prison on the Capitoline Hill. Tarquinius Priscus was the fifth king of Rome and the first of Etruscan birth. After emigrating to Rome, he gained favor with Ancus, who later adopted him as his son. Upon ascending the throne, he waged wars against the Sabines and Etruscans, doubling the size of Rome and bringing great treasures to the city. Following Priscus’s death, his son-in-law Servius Tullius succeeded him to the throne, the second king of Etruscan birth to rule Rome. Like his father-in-law before him, Servius fought successful wars against the Etruscans. He used the booty from the campaigns to build the first walls to fully encircle the Seven Hills of Rome, the pomerium. He also made organizational changes to the Roman army. The seventh and final king of Rome was Tarquinius Superbus. As the son of Priscus and the son-in-law of Servius, Tarquinius was also of Etruscan birth. It was also during his reign that the Etruscans reached their apex of power. More than other kings before him, Tarquinius used violence, murder, and terrorism to maintain control over Rome. He repealed many of the earlier constitutional reforms set down by his predecessors. Tarquinius removed and destroyed all the Sabine shrines and altars from the Tarpeian Rock, enraging the people of Rome. A sex scandal brought down the king. Allegedly, Tarquinius allowed his son, Sextus Tarquinius, to rape Lucretia, a patrician Roman. Sextus had threatened Lucretia that if she refused to copulate with him, he would kill a slave, then kill her, and have the bodies discovered together, thus creating a gigantic scandal. Lucretia then told her relatives about the threat, and subsequently committed suicide to avoid any such scandal. Lucretia’s kinsman, Lucius Junius Brutus (ancestor of Marcus Brutus), summoned the Senate and had Tarquinius and the monarchy expelled from Rome in 510 BC.
Etruscan rule in Rome, according to tradition, then came to a dramatic end in 510 BC, with the expulsion of Tarquinius Superbus, which also signaled the downfall of Etruscan power in Latium, the gradual cessation of Etruscan influences at Rome, and the establishment of a Republican constitution.
Many years later during the Republican period, this strong Roman opposition to kings was used by the Senate as a rationalization for the murder of the agrarian reformer Tiberius Gracchus. Lucius Junius Brutus and Lucius Tarquinius Collatinus, a member of the Tarquin family and Lucretia's widower, went on to become one of the first consuls of Rome’s new government. This new government would lead the Romans to conquer most of the Mediterranean world and would survive for the next 500 years until the rise of Julius Caesar and Caesar Augustus. Even then, the trappings of the Republic were not entirely done away with; the Republic would survive in a debased form until the Dominate.