The first habitations were perhaps cave-dwellings, but it was not long before stone-built huts were erected. Many villages of such huts are known, one of the best examples being that at Gonessa in the south-west of the island. The little houses them selves were mostly round, and about loft. in diameter; inside they were furnished with benches, stalls for animals, and an altar near the entrance. In a strategic position near the huts were dwellings of grander character, perhaps the residences of chief tains, but fortified so that they might serve as watch-tower, refuge and defence for the whole village in times of danger. These are the nuraghi, double-storeyed towers in the shape of a truncated cone and built of large stones laid in regular horizontal courses, sometimes with the aid of a clay mortar. They are generally about 25 to 35ft. in diameter and about 4oft. in height, and in their usual form they contain an upper and lower chamber with tall and pointed corbelled roofs connected by a winding staircase; but sometimes they have several communicating chambers built bastion-wise against the tower on the ground level; or, again, the nuraghi proper may form part of a completely fortified en closure that is protected by an additional tower. The nuraghi are sometimes furnished with embrasures or loop-holes, as at Losa, Giara and Santa Vittoria, and there is no doubt that they were primarily forts, all the constructional details being arranged with a view to tactical advantage in defence. The nuraghi, how ever, were not exclusively used in times of war, for many show abundant evidence of ordinary domestic occupation, and of use as bronze foundries; e.g., Ortu Commidu near Sardara. The intimate connection between village-life and the nuraghi is best illustrated on the plateau Giara di Gesturi, for this has no less than seventeen nuraghi set round its edge to defend the big cluster of huts on the top of the plateau. Here there is evidence of occupation extending from the copper age until the Roman period.
Though the earliest settlers lived in caves, and it is in caves that their burials are found, the tombs of the nuraghi-civilization are artificially constructed, and of three different kinds. The best-known are the Domus de Gianas (witches' houses), compli cated artificial grottoes of which there are famous examples at Anghelu Ruju and S. Andrea Priu. In plan they show a nest of burial-cells communicating by means of narrow passages with an antechamber. This last was seem ingly used for devotional and religious purposes, for it is some times painted red and decorated with carvings ; while inside are pillars, also carved with cult symbols, and stone troughs and hearths. The dead were buried in the cells in a crouched position and accompanied by rich grave goods including stone axes, mace heads, arrowheads, copper daggers, axes and awls, personal orna ments and amulets of many varieties, and pottery that included (at Anghelu Ruju) bell-beakers, a supposed link with the Spanish beaker-culture. The second and contemporary type of grave is a polygonal or rectangular megalithic structure, at first little better than a stone-lined pit, but passing into regular cist-forms. These rectangular chambers, however, are not numerous, and much more common is the third type, an obvious derivative of the cist, known as Tombe dei Giganti (giants' graves). In these a rectangular
chamber with a corbelled roof is encased in a stone-edged mound with crescentic horns, and in the centre of this curved façade, and at the head of the chamber, is a gabled and panelled portal slab with a small hole at its foot, or, alternatively, a door of two up rights and a lintel. The chambers vary from 24ft. in length to as much as soft., and doubtless served as graves for whole families, or even whole villages. In addition to these villages and graves, it remains to note the existence of a number of menhirs.
There was no Greek colonization in the formal sense although Greek historians have recorded that such colonization was pro jected (Herodotus, I., i7o) and was achieved (Pausanias, X., 17, 5). Nevertheless, Olbia and Neapolis, as their names imply, were doubtless founded by Greeks, and there must have been more than one short-lived Greek settlement in the island. But the first serious interruption of the nuraghi-civilization was an occupation by Carthage about Soo to 48o B.C. that resulted in the exploitation of Sardinia as an important grain-growing land, and in the foundation of such towns as Cornus, Tharro and Sulci. The island remained a Carthaginian colony until 238 B.C. when it was ceded to Rome, and a struggle began between the natives and their new masters. Roman conquest was, however, inevitable, and in a short while the island was organized as a province that ultimately became one of the main corn-supplies for Rome.