Tarquinia (Italian: [tarˈkwiːnja]), formerly Corneto, is an old city in the province of Viterbo, Lazio, Italy, known chiefly since it was (mis-)named after the ancient city of Tarquinii (Roman) or Tarch(u)na (Etruscan), although it was built across the valley on the opposite hill to that city, and overlies some of its widespread ancient cemeteries. Little is visible of the once great wealth and extent of the ancient city, but archaeology is increasingly revealing glimpses of past glories.
Tarquinii (Etruscan Tarch(u)na etc.) is one of the most ancient of Etruscan cities; the ancient myths connected with Tarch(u)na (those of its eponymous founder Tarchon - the son or brother of Tyrrhenos - and of the infant oracle Tages, who gave the Etruscans the "disciplina etrusca"), all point to the great antiquity and cultural importance of the city; and the archaeological finds bear out that Tarquinia was one of the oldest Etruscan centres which eclipsed its neighbours well before the advent of written records. It is said to have been already a flourishing city when Demaratus of Corinth brought in Greek workmen. It was the chief of the twelve cities of Etruria.
In Rome's early semi-legendary history, Tarquinia was the daughter of Lucius Tarquinius Priscus, the fifth king of Rome, and brother to Rome's seventh and final king, Lucius Tarquinius Superbus. She was the mother of Lucius Junius Brutus, who overthrew the monarchy and became one of Rome's first consuls in 509 BC. She had another son, who was put to death by Superbus.
Tarquinius (plural Tarquinii; compare the place name Tarquinia) is the gens name (nomen) of a Roman family of Greco-Etruscan origin. Two Tarquins were among the semi-legendary kings of Rome.
The names on the list of kings indicate that the Roman monarchy was not hereditary. The presence of two Tarquins, the last of whom was ousted as a tyrant, may indicate that the family attempted to monopolize power within the family contrary to Roman custom. According to tradition, the precipitating event was the rape of Lucretia by Sextus Tarquinius, the king son. The expulsion of the Tarquins signaled the end of the Regal period and the beginning of the Republic in Roman history.