The Judicate of Cagliari occupied the entire southern portion of the island and was composed of thirteen subdivisions called curatoriae.

Sardinia remained a Byzantine province until the early 8th century, when Arab and Berber expansionism and piracy on the Mediterranean began to make communications with Byzantium very difficult.

As the empire found it increasingly difficult to supply and defend its westernmost provinces, the Byzantine iudici (judges) heading the local administration in Sardinia were forced to govern autonomously and thus gradually became de facto independent.

Cagliari, the capital in turn of the Roman, Vandal and Byzantine provinces of Sardinia, was historically the largest and most important of the cities on the island.

Santa Igia then became the capital of the Judicate of Cagliari, one of the four kingdoms that evolved when imperial power receded in the West.

The Judicate of Cagliari comprised a large area of the Campidano plain, the mineral-rich Sulcis region, and the mountainous Ogliastra.

Torchitorio was a sponsor of the monks of Monte Cassino who were arriving on the island to bring economic, technological, and religious renewal.

Cagliari lost the war and in 1258 the history of the giudicato came to a sudden close; his territory was partitioned in three parts that were assigned to the Della Gherardesca family, Arborea and Gallura while Pisa maintained the control over Castel di Castro.