Villasimius, Old Fortress

The tower controlled the port of Capo Carbonara, already attested since 1566 and frequented by coralleros and fishermen, as well as the mouth of the Rio di Carbonara, a possible mooring for supplying water and wood for possible pirates. The fortress, overlooking the sea, was visible from the towers of Capo Boi, Porto Giunco and Cala Caterina.
The Capo Carbonara Peninsula and neighboring coasts were patrolled by a surveillance system since the beginning of the 16th century at the expense of the city of Cagliari. But in 1572 the area had no fortifications, although there was a structure in the port, perhaps corresponding to the central nucleus of the current fortress, on which the Spanish intervention of the years 1580-90 was grafted.
Originally, the fortress had an equilateral triangular plan, with sides of about 11 m, a wall thickness of about 1.20 m and a height of about 10 m. The raised entrance was facing the sea, protected at the base by a sheath, that is, by an additional lower, V-shaped work. Within this wall, already at the end of the 16th century, the boats of coral reefs and tuna fishermen were sheltered.
In 1590 - 91, a garrison was installed in the 'Fortalesa Biesa de Carbonayre' to defend the tuna trap. A document from 1599 shows that the tower was included in the fourth division (which starts from the slopes of Villanova to Sarrabus). Since then, it has acquired an increasingly important role, performing the functions of guard and defense.
In Savoy times, in 1767, as can be seen from the Ripol report, the tower housed a captain, three soldiers and two cannons. As for its maintenance, several repairs were necessary since 1720. Restored in 1769-70 on a design by the engineer Belgrano da Famolasco, in 1790 it underwent a second, more radical intervention. Designed by engineer Quaglia, the triangular keep was transformed into a small complex with four sharp-edged lobes, with mini bastions attached to the top of the triangle. This scheme allowed the elimination of blind spots at gunfire in close encounters. Overall, the basic planimetric pattern was not changed, remaining unchanged to this day.
In 1803, other restoration works were carried out. In 1812, it appears that the tower repelled an attack by barbarians who had conquered the towers of Serpentara and the Island of Cavoli. The fortress therefore remained in operation until 1847, when the last 'alcaide' (captain of the tower) was fired. The tower was abandoned until 1968, when a restoration was carried out by the Superintendence of the BAAAS of Cagliari, which lasted until 1973. In 1987, other maintenance and excavations were also carried out in the area of the enclosure.

History of studies
The fortress is included in the main works on coastal fortifications in Sardinia and is the subject of a fact sheet in the volume by Francesca Segni Pulvirenti and Aldo Sari (1994).

Bibliography
E. Pillosu, The coastal towers in Sardinia, Cagliari, La Cartotecnica Typography, 1957;
E. Pillosu, “An unprecedented sixteenth-century report on the coastal defense of Marco Antonio Camos”, in New Sardinian Bibliographic Bulletin and Archive of Popular Traditions, V, 1959;
F. Fois, Spanish Towers and Piedmontese Forts in Sardinia, Cagliari, The Sardinian Voice, 1981; J. Arce, Spain in Sardinia: cultural contributions and testimonies of its influence, Cagliari, T.E.A., 1982;
G. Montaldo, The coastal towers in Sardinia, Sassari, Carlo Delfino, Sassari, 1992;
F. Russo, The coastal defense of the Kingdom of Sardinia from the 16th to the 19th century, Rome, Army General Staff, Historical Office, 1992;
F. Segni Pulvirenti - A. Sari, Late Gothic and Renaissance-influenced architecture. Nuoro, Ilisso, 1994, sheet 21;
M. Rassu, Guide to coastal towers and forts, Cagliari, Artigianarte, 2000.