During the late 2nd millennium B.C. in the Bronze Age, a special type of defensive structure known as nuraghi (for which no parallel exists anywhere else in the world) developed on the island of Sardinia. The complex consists of circular defensive towers in the form of truncated cones built of dressed stone, with corbel-vaulted internal chambers. The complex at Barumini, which was extended and reinforced in the first half of the 1st millennium under Carthaginian pressure, is the finest and most complete example of this remarkable form of prehistoric architecture.
During the Middle and Late Bronze Ages (c 1500-800 BC) on Sardinia a unique form of architecture developed: circular defensive towers in the form of truncated cones built of dressed stone, with corbel-vaulted internal chambers. Some (as at Barumini) were surrounded by quadrilobate enclosures consisting of towers linked by massive walls. Villages of small circular-plan houses developed around these strong-points.
The precise dating of the period of building the nuraghi on Sardinia is still the subject of debate among scholars, since there is some conflict between radiocarbon dates and those obtained by conventional archaeological stratigraphy. The influence of the Mycenaean tholos tombs, reflected in the corbelled roofs, now favours an earlier rather than a later dating. It is generally accepted that the central tower at Barumini dates from the later 2nd millennium BC.
The central defensive structures are considered to have been built by single families or clans. As Sardinian society evolved in a more complex and hierarchical fashion, there was a tendency for the isolated towers to attract additional structures, for social and defensive reasons.
The major effort towards the extension and elaboration of the defensive works at Barumini is dated to the Early Iron Age (10th~8th centuries BC), when Sardinia was exposed to Carthaginian incursions. It is significant that the larger nuraghic settlements of this type are located on those parts of the coast, or on the wide coastal plain of the eastern half of the island (as is the case of Su Nuraxi), that were most vulnerable to seabome attacks. It was during this period that the defences at Barumini and elsewhere were strengthened and the villages accreted around the central defences for protection. They became in effect small urban settlements, housing self-sufficient communities with their own range of craftsmen.
Some time in the 7th century BC Su Nuraxi was sacked by the Carthaginians and the defensive works were slighted. However, it continued as a settlement, the houses being rebuilt in a different style. With the Roman conquest of the island in the 2nd century BC most of the nuraghi went out of use. However, excavations have shown that there were people living at Su Nuraxi until the 3rd century AD.