The Giudicati were independent states that took power in Sardinia between the ninth and fifteenth centuries. They were sovereign states with summa potestas (all the powers), each ruled by a King called Judge (Judike in Sardinian).
The almost total absence of historical sources does not allow certainty surrounding the date of the passage from Byzantine central authority to self-government in Sardinia. It is believed that at some point the Iudex Provinciae, perhaps the praeses, of Caralis had complete control of the island. He appointed, in the most strategic area for the defence of the coast, the lociservator (lieutenant) who became substantially autonomous from Caralis over time; this was probably the action that precipitated the birth of the Giudicati.
The known medieval giudicati were:
- Giudicato of Cagliari (with capital in Santa Igia, nearby the modern Cagliari)
- Giudicato of Arborea (with capital in Oristano),
- Giudicato of Gallura (with capital in Olbia)
- Giudicato of Logudoro (with capital in Porto Torres, Ardara and then Sassari)
The administrative organisation of the Giudicati differed significantly from the feudal forms existing in the rest of medieval Europe
In the international context of the Middle Ages, the Giudicati were characterised by semi-democratic institutions such as the Coronas de curatorias which in turn elected their own representatives to the parliamentary assizes called Corona de Logu.
Particularly important for the period was the Carta de Logu. It was a legal code of the Giudicato of Arborea, written in the Sardinian language and promulgated by the iudex Eleanor in 1392. It was in force in Sardinia until it was superseded by the code of Charles Felix in April 1827.
The Carta was a work of great importance in Sardinian history. It was an organic, coherent, and systematic work of legislation encompassing the civil and penal law. The history of the drafting of the Carta is unknown, but the Carta itself provides an excellent glimpse into the ethnological and linguistic situation of late medieval Sardinia.