History of Sardinia
In the Early Middle Ages, through barbarian movements, the waning of the Byzantine Empire influence in the western Mediterranean and the Saracen raids, the island fell out of the sphere of influence of any higher government. This led to the birth of four kingdoms called "Judicates" (Latin: "Judicati"; Sardinian: "Judicados") in the 8th through 10th centuries. Falling under papal influence, Sardinia became the focus of the rivalry of Genoa and Pisa, the Judicates and the Crown of Aragon, which eventually subsumed the island as the Kingdom of Sardinia in 1324. The Kingdom was to last until 1718, when it was ceded to the Piedmontese House of Savoy; later, in 1861, it would thus become the Kingdom of Italy and finally in 1946 the Italian Republic.
Poggio Mirteto
In the end of the year 1860, similarly to other Papal States territories, Poggio Mirteto joined the Kingdom of Sardinia during the fast events which arranged the making of the Kingdom of Italy that happened in the next year. The then Special Commissioner for the Province of Umbria of the Kingdom of Sardinia, Gioacchino Napoleone Pepoli, created by decree the Province of Umbriaon 15 December 1860, merging the previous Districts of Perugia, Spoleto, Orvieto, Foligno, Terni and the one of Rieti; therefore Poggio Mirteto, which was in the Rieti District, was included in this new Province.