The island of Sant'Antioco is connected to the S/O coast of Sardinia by an artificial isthmus. Calasetta is on the opposite side.
Calasetta represents the second settlement unit - in chronological order - built in Sardinia by the will of the Savoy government.
In 1754, the Secretariat of State of the Kingdom of Sardinia planned a first colonization of the island of Sant'Antioco, at the N end near the Calasera cove and the mouth of the Topei River but, due to disputes with the Archbishop of Cagliari, who advanced rights to exploit the island, the project did not take place.
Only a few years later, in September 1770, a community of Tabarchini (people of Ligurian origin who since the 16th century had moved to the town of Tabarka, near Tunis, to practice coral fishing in the surrounding waters) arrived on the island, who two years earlier had submitted a request to the Sardinian government to be able to move to the island of Sulcita. The Order of the Sacred Religion of Saints Maurice and Lazarus was responsible for the transfer and settlement of the colonists, to which in 1758 King Charles Emmanuel III of Savoy granted the island as a fief with the task of repopulating it.
The project of the new foundation, developed by the lieutenant of artillery Belly, involved a town that developed according to the grid pattern that still characterizes it today. Once the fulcrum of the town (corresponding to the current Piazza Municipio) was identified, the Belly traced the main axis (now Via Roma), oriented N/E-S/O, on which the other road axes would have intersected at right angles. Each housing unit, to be built with stone and mixed earth, would have had a courtyard, the stable, the barn and the vegetable garden; the common water reserve would have been located in the center of the square, while the parish church would have been built on the N side of the square itself.
The protection of the territory was ensured by the mighty tower that still dominates the historic center of the town today. Built in 1756 according to the design of the military engineer Vallin, it was guarded by a garrison formed by four soldiers and allowed the surveillance of the sea mirror and the coasts between the islands of Sant'Antioco and San Pietro and the mainland, with a view of 20 km.
Made of volcanic stone blocks on a rocky base at the top of the promontory towards Carloforte, it has the classic shape of a trunk of cone with a base diameter of more than 16 m and a height of 11 m at the terrace. It consists of two overlapping rooms, the lower one of which was the ancient tank, the only water resource for tower workers, expanded in recent times and equipped with a large entrance from the outside. The entrance at 4 m above sea level leads into a circular chamber of 10 m in diameter, covered with a dome supported by a pillar. The room is divided into several rooms by some terraces. From the open staircase on the right of the hatch and cut into the thick wall, you arrive at the parade ground, now unrecognizable after several interventions that have transformed Merloni, gunner and box office. The tower is currently home to temporary exhibitions and cultural activities.
The parish church, named after Saint Maurice, was built only in 1838 and on a different site from that foreseen in the Belly project, to prevent its size from disturbing the view from the tower. With its central plan, timpanated façade and two small domed bells, it is attributed to a first design by Belgrano di Famolasco, then to a classical transformation carried out by Carlo Pilo Boyl in the early nineteenth century.

Bibliography
V. Angius, entry “Cala-seta”, in G. Casalis, Historical, Statistical-Commercial Geographical Dictionary of the States of His Excellency the King of Sardinia, III, Turin, G. Maspero, 1836, pp. 305-306; M. Cabras-P.
Rvano Poma, Calasetta. History and literary folklore, Cagliari 1980;
F. Fois, Spanish Towers and Piedmontese Forts in Sardinia, Cagliari, 1981;
G. Montaldo, The coastal towers of Sardinia, Sassari 1992;
D. Pinna, “The Island of Sant'Antioco from the Middle Ages to the Present Day”, in The Sulcitan Islands, edited by N. Sciannameo, Cagliari, 1994, pp. 106-111; D. Cipollina, “The 'Little Turin'.
Calasetta, the town of right-angled streets that recall the urban planning solutions of the Piedmontese capital”, in Sardinia Fieristica, 1998, without pages;
M. Rassu, Guide to coastal towers and forts, Cagliari, 2000.