The castle of Monreale was one of the main strongholds of the Giudicato of Arborea, i.e. one of the four Sardinian independent kingdoms (Cagliari, Arborea, Torres or Logudoro, Gallura), which were formed between the VIII and IX centuries as a result of the isolation which was forced onto the island following the dissolution of the Byzantine Empire in the West and the Arab expansion in the Mediterranean (fig. 1) .

Fig. 1 - Coat of arms of the Giudicato of Arborea (from http://it.wikipedia.org/wiki/Storia_della_Sardegna_giudicale).

Arborea initially stretched over central-western Sardinia, which corresponds roughly to the current province of Oristano; it bordered to the north with the Giudicato of Torres, to the east with the Giudicato of Gallura and to the south with the Giudicato of Cagliari.

Its capital was initially Tharros and, from 1076, Oristano. It was divided into fourteen curatorie: Austis, Barbagia of Belvì, Barbagia of Ollolai, Barigadu, Bonorzuli, Campidano Maggiore, Campidano of Milis, Campidano of Simaxis, Guilcer, Mandrolisai, Marmilla, Montis, Usellus and Valenza (fig. 2).

Fig. 2 - The curatorie of the Giudicato of Arborea (from http://upload.wikimedia.org/wikipedia/commons/9/9f/Giudicato_di_Arborea_2.svg).

Beginning in 1250 the sovereigns of Arborea managed to annex land portions of the other kingdoms, by now extinct, occupying Planargia, Goceano, the Nuoro area, the Iglesiente, the Campidano of Cagliari, almost achieving total control of the island.

Its history continued until 1420, when the last king of Arborea, William III of Narbonne, ceded what was left of the ancient kingdom to the Crown of Aragon for 100,000 gold florins . The Giudicato was governed over time by the dynasties of Lacon-Gunale, Lacon-Serra, Bas-Serra and Cappai de Baux.

Mariano IV stands out among its most famous rulers and ruled in an enlightened way for several decades, as does his daughter Eleanora of Arborea (fig. 3), who ruled as regent for her children from 1383 to 1403, when, according to tradition, she died possibly due to the plague .

Fig. 3 - Eleonora d’Arborea signs the Carta de Logu, by Antonio Benini (late nineteenth century). Oristano Palazzo Campus Colonna (from http://www.turistiaoristano.com/2012/05/il-vero-ritratto-di-eleonora-darborea.html).