The province of Viterbo is located in northern Lazio, on the border with Umbria and Tuscany. It has an ancient origin and a vast medieval historical center, surrounded by walls and surrounded by modern districts, except to the west, where archaeological and thermal areas extend. Viterbo is historically known as the City of the Popes. In the XIII century, in fact, it was the papal seat and for about 24 years the Papal Palace hosted several Popes. Pope Alexander IV decided in 1257 to transfer the Papal Curia to the city because of the hostile climate in Rome; the papal stay lasted until Pope Martin IV, just elected (February 1281), definitively removed the papal court from Viterbo.

The city is famous for the transport of the Santa Rosa Machine, a traditional and spectacular event that takes place every year on the evening of September 3, in honor of the patron saint: an illuminated structure, 30 meters high and weighing 52 quintals, is brought on the shoulders of a hundred men, the Facchini of Santa Rosa, through the streets of the city. In 2013 the Machine was included by UNESCO as an Intangible Heritage of Humanity.

The origins date back to the Neolithic and Eneolithic thanks to various Etruscan remains, especially in the subsoil. Some historians are led to believe that in the Etruscan period the settlement did not reach the vicus state, while other historians even assumed that there was an Etruscan tetrapole on site. More certain news is had for the High Middle Ages, which originates from a "castrum", ie a Longobard fortification placed at the border between the Longobard possessions in Tuscia and the Byzantine duchy of Rome: the hill of San Lorenzo.