Few are the informations that the ancient sources (Cicero, Dionysius of Halicarnassus, Livy, Strabo, etc.) handed down to us about the history of Tarquinia, but those still describe the city as one of the most important of all Etruria.
Tarconte, son of the hero Tirreno, the king of Lydia who led the Tyrrhenians (the Etruscans) in Italy, founded the city and gave it its name. In Tarquinia would also have appeared the divine child Tages, who taught the Etruscans the fundamentals of haruspicy, namely the divination practice obtained through the inspection of sacrificed animal entrails for which the Etruscan priests were famous for centuries. At Tarquinia was also set the origin of the Tarquin dynasty, the Etruscan kings who reigned in Rome between the late 7th and the 6th centuries BC.

Archaeological investigations have shown that the origins of the historic age Etruscan city are going back in time up at the end of the Bronze Age in the 10th century BC.
Tarquinia, like the other great Etruscan cities of the Tyrrhenian Sea, stands few miles from the shore and the site selection corresponds perfectly to the Cicero's observation in the De Republica (II, 3-4) that states that a city must be far enough from the sea to protect herself against the dangers that may come from there, but close enough to it as to take advantage of trade. The long process of urban formation on the Civita plateau lasted throughout the Iron Age (Villanovan period, 9th-8th centuries BC) and saw the gradual development of a large village of huts, surrounded by several necropolis and by small villages subordinated to the main dwelling of La Civita. The Villanovan Tarquinia is very rich and plays a dominant role over other near towns, perhaps because of the control over the Tolfa mineral-rich mountains. The contact with the Greek world, that undergoes a profound incrementation with the creation of the first commercial base on the island of Ischia and the founding of the first colony - Cuma - on the coasts of Campania, accelerates and influences the social transforming process already in act within the Villanovan community.

The urban formation process is concluded in the final decades of the 8th century BC and the town in the successive Orientalizing period (late 8th-7th centuries BC) gradually transforms itself from a village of huts in a town of masonry houses. These were initially reserved for the dominant aristocratic class that emerged during the 8th century BC and that now sees its economic and political power definitively consolidated. At the dwelling transformation correspond similar monumentalizations of the necropolis: the most important of these took place on the Monterozzi hill, a height parallel to the Pian di Civita between this and the Tyrrhenian coast. Here were made the first chamber tombs carved into the bedrock and marked on the surface by earth mounds: they were reserved for the burial of princes and priests whose precious grave goods show the complex and large trade contacts established by Tarquinia not only with the other peoples of ancient Italy, but also with those of the eastern Mediterranean.
In the 6th and in the early decades of the 5th century BC Tarquinia is at its urban apogee. Witness of the economic and political splendour of the city are now the numerous "painted tombs" of the Monterozzi necropolis, but also paradigmatic of the city power is the Gravisca harbour and the sanctuary-emporium located on its edges: built in the early 6th century BC, the Tarquinian port received foreign merchants coming mainly from the eastern Mediterranean that were followed by craftsmen and artists ready to meet the sophisticated needs of the rich local aristocracy. In the town, on La Civita, for this period there are clear traces of intense building activity (temples, public and private buildings, etc.). From the second quarter of the 5th century BC Tarquinia, like all the great Etrurian cities on the Tyrrhenian Sea, is interested by a process of economic recession resulting from a socio-political crisis, but soon - at the beginning of the next century - the city rises again and lives new decades of great splendour. It now takes command of the Etruscan cities federation mobilized in defence not only from the Celtic threat coming from the north, but also from the more dangerous one from the south: the Roman power.
The ancient sources in fact talk about battles between Tarquinia and Rome in the beginning of the 4th century BC, concomitantly with the fall of Veii. This new period of prosperity involves the resumption of construction activities with the restoring, on the Civita, of the main city buildings, first of all the great Ara della Regina temple. The city has also equipped itself now with an imposing fortified wall 8 km long, in view of the final clash with Rome dated, as the ancient historians tell us, to the 358-351 BC. After a series of war events alternating with cease-fires, Tarquinia will see confiscated, in the first half of the 3rd century BC, the coastal land where a century later, on the site of the ancient port of Gravisca, now in disuse, Rome will create in 181 BC a maritima civium Romanorum colony. After 90 BC Tarquinia, like the other Etruscan towns, receives the Roman citizenship and becomes a municipality governed by four magistrates.

(from M. Cataldi, Tarquinia. Museo Archeologico Nazionale. Guida breve, Roma 2001)