The village of Tessennano is perched on a hill protected by perimeter walls, and there is no news about its ancient history even though the name is of Etruscan origin and the legend says it was founded by Ascanio, son of Aeneas.
Certainly this was a staging post for those who were travelling between Tuscania and Canino. In the Middle Ages it was under the control of the Church. After a period under the rule of Siena, in the fifteenth century it fell halfway between the Orsini and the Farnese. In 1537 it was included in the Duchy of Castro created by Paolo III for his son Pier Luigi Farnese.
In 1644 Ranuccio II, son of Odoardo Farnese, burdened with large debts, gave the duchy to Pope Innocent X and Tessennano passed thus in fact under the jurisdiction of the Apostolic Camera. Several feudal families then succeeded to govern it.