The city of Tharros, located at the southern end of the Peninsula of the Sinis, was probably founded at the end of8th century BC. from Phoenician peoples in an area already frequented in the Nuraghic age.
On one of the three hills on which the city stands, the northernmost, known by the name of Murru Mannu (in Sardinian "big snout"), an important one is still visible today village of nuragic age (Middle-Late Bronze Age). Also on the hill of San Giovanni there are nuragic traces: underneath the tower of the same name, built by the Spaniards in the 16th century, the remains of a nuraghe were found, placed under control of the height. Finally, on the Capo San Marco there is a small nuraghe, which further clues to the interest of the nuraghic peoples for the area, given the strategic importance for the control of the territory.
In the second half of the sixth century, moment of great changes due to the prevailing expansionist policy of Carthage, Tharros does not escape the conquest by the African metropolis. The monumentalization of the city must refer to the Punic age. In the period between the end of the sixth century and the 238 BC, year of the Roman conquest of the island, many buildings are built that are still partly preserved under those of a later age.
At the Punic age some of the most important places of worship of Tharros are also to be reported. These include the so-called monumental temple o "Temple of Doric semicolumns". Beginning with the Roman conquest of the island, which took place in 238 BC, the process of profound change began, which will only take place in the Imperial Roman age.
Ad Republican age the resettlement of the fortifications of Murru Mannu is attributed. It is however in imperial age that the city undergoes the greatest changes: an imposing urban reorganization is carried out with the organization of a sector of the city, the one on the Murru Mannu hill, with the reorganization of the road system and consequently of the living quarters. Around the II century AD the streets are equipped with a basalt paving, also providing a very articulated sewage system that guarantees the disposal of white water.
The aqueduct must still be attributed to the imperial age, the remains of which are partly visible along the modern road that leads to the excavations. As for the funeral areas, they appear larger and more extensive than in the previous period. The Punic necropolis of Capo San Marco and St. John are still frequented, especially in the first centuries of the Roman conquest, but there is an expansion of the same, in the first case invading the entire isthmus up to the hill of St. John, in the second moving inward, with important attestations also in the area where in the Byzantine age will rise the church of St. John Baptist.
In Paleochristian age e Early Medieval the main Roman structures undergo modifications, some baths are transformed into a basilica building, which is considered by some to be an episcopal seat, others change in use, as the presence of Byzantine burials suggests.
The continuous stripping of ancient structures, perpetrated for centuries, has greatly undermined the reconstruction of this late phase of the center's history. We know of a slow decline, also due to the raids by the Saracens, and a progressive depopulation, although the episcopal see remained in the city for a long time. It is only in the XI century, precisely in the 1071, that the episcopal see is transferred to Oristano, decreeing, or rather taking note, of the end of the ancient center.