The origins of the village of Pettorano Sul Gizio start from the Middle Ages, but the surrounding area and the hills near the village have been known to man since Paleolithic times. Research conducted on the slopes of Mount Genzana and in other surrounding areas have provided ancient testimonies, especially tools that belonged to the first hunters who visited and sporadically inhabited these lands. The archaeological evidence found here has enabled us to monitor the area from the Middle Ages, through the development of the first settlements and the activities of these ancient inhabited lands of the upper valley of the Gizio river.
The origins of the present village are to be found in the medieval period, precisely at the stage when the dwellings were united into one urban complex for defensive political and economic reasons. A historian from Pettorano of the 19th century, Nicola Bonitatibus, described very well the formation of Pettorano: "Undeci, ed anche più si vuole che fussero le Ville, le quali, unitesi in società circa il decimo secolo, si determinarono ad eriggere Pettorano nel luogo dove al presente si vede. Lo circuirono di muri, e di torri, e lo munirono d’una fortezza, per far fronte a comuni inimici, ed agli invasori”.