The Sassatelli family was one of the most powerful of the town during the XV to XVIII centuries, but for sure Giovanni - nicknamed 'Cagnaccio' (Mad Dog) for his shrewdness and violence, was the most famous. His adventures took place in the violent period of town fights between the Pope’s supporters (Guelfi) and the Emperor’s supporters (Ghibellini). Giovanni Sassatelli was a leader of the Guelfi and he fought against Guido Vaini, leader of the opposition. The hostility between the two families brought on much violence which reached the climax on the night of 21st June 1504 when the Vaini supporters attacked their rivals who were barracked up in the family mansion, the present Palazzo Monsignani. It was Giovanni himself who changed the course of the battle, by coming in aid with his 150 soldiers: for the Vaini ’s soldiers it was a massacre which happened in the small side-street which was then renamed Vicolo Inferno (the street of hell) because of the blood that was shed.