The origins of the town of Viterbo transpire from archaeological finds, discovered over the centuries, indicating the existence, since the beginning of the Neolithic, a native Etruscan population: around the town of Viterbo, and the finds at the tombs of the Riello it bear witness.
In the eighth century of the Christian era, the castrum Viterbi attracted the attention of King Desiderio, the last king of the Lombards, who, wishing to invade the Duchy of Rome, came here with a strong army, and fortified the city Viterbo with mighty walls and towers and it made his base, from which the conquest of the Eternal City.
It was appalled by the excommunication by Pope Adrian I sent to him, but perhaps also by the army of Charlemagne, king of the Franks, that the Pope had called in to help, so he abandoned his plans of conquest and quickly went back to Tuscany.
The City of Viterbo drew many benefits, in that, fortified as it was, attracted people from neighboring villages and Lombard many decided to stay. Viterbo thus began to acquire political and military importance of the whole territory and to grow considerably. In the following centuries the city of Viterbo faced the raids of the Turks, who had taken possession of Civitavecchia and those of the Normans. In 1148 the city of Viterbo became a free Commune, enacting its statute in 1251, one of the first examples in Italy. At Viterbo, still called the City of the Popes, were kept in the thirteenth century, several conclaves (the Cardinals meeting for the appointment of the Pope), including the longest in history, indeed the very word conclave has been used for the first Viterbo kept closed when the time cum clave (key), precisely in the papal palace, the cardinals to elect to hasten the Pope during the struggles between the Papacy and the Empire, the city of Viterbo had ups and downs, the Emperor Frederick II, the granted various privileges, including the right to coin money, Viterbo became the capital of the Patrimony of St. Peter, that of all the lands donated to the Church; Viterbo bishopric was erected in 1192. History tells us that until the fourteenth century were undertaken continuous struggle for supremacy in the territory of Viterbo, first among the leading families, then against Rome and finally against the emperors. It was an ongoing war for the acquisition of nearby villages and for dominance over the city of Viterbo..
Viterbo returned in the following centuries under the domination of Rome, following the fortunes since then. Viterbo continued to attract visitors from all over the world, not only as an obligatory stop on the Via Francigena from England, through France, brought the pilgrims to Rome to St. Peter's tomb, but because the fame of the miracles of the Holy Maiden named Rosa, the patron of the city, attracted by his monastery emperors, heads of state and people of all rango.Viterbo owes its importance to its mineral spring waters that flow around the city and made it famous since ancient times for its sulphurous waters that have fueled the numerous Etruscan and Roman thermal baths, whose ruins are scattered throughout the territory. Currently, the baths of Viterbo, with water flowing to the source of Bulicame to 52 ° C, depending on the hotels and spas equipped with sophisticated equipment.