The Fortress, is entered from Piazza Campello below. At present it is open only for brief visits and on rare occasions because it is being restored. It was commissioned in 1362 by the pontifical legate, Cardinal Albornoz (historical notes) who entrusted its construction to the architect from Gubbio, Matteo Gattapone. This impressive building has a rectangular plan with six mighty towers around its permeter. These towers are joined by walk-ways which divide the internal area into two: the military courtyard for the troups and the courtyard of honour for the private use of the city governer. At the centre of this courtyard there is a charming well bearing the pope's heraldic arms. The courtyard itself is surrounded by a portico on two floors. A large hall looks out onto it, together with the room of the lord of the castle which is called the Camera Pinta (painted room), with noteworthy frescoes which recent restoration has brought back to life.

The Fortress was once an impregnable residence for nobility and their illustrious guests. During the nineteenth century it lost its original function when it was transformed into a jail and was radically efaced. In 1983 the Fortess was finally returned to the city of Spoleto under the tutelage of the Ministry for Cultural Affairs. Since then restoration has been in progress slowly and carefully bringing the Fortress back to its original state.