It is an imposing fortress on the top of Colle Sant'Elia, the highest point in Spoleto.
Its construction began in the year 1359 and was completed around the year 1370, under the supervision of Matteo di Giovannello from Gubbio, known as "il Gattapone".
The fortress, renamed after the powerful Spanish Cardinal Egidio Albornoz, was commissioned by Pope Innocenzo VI during his permanence in Avignon (France) to re-establish his authority in the central teritories that belonged to the Papal States.
The fortress has changed its function many times over the centuries.
Designed to be the official residence of the Governors of the city, with richly decorated interiors, it was later turned into a prison (1817) until the year 1982.

The recently restored fortress with its rectangular shape and six imposing towers, consists of two courtyards, one of which was originally the seat of the armed militia (Cortile delle Armi), while the other was reserved to the administrators and governors (Court of Honor).
An arch, decorated at the end of the 16th century with frescoes depicting six cities that belonged to the Papal States connects the two courtyards.
The rooms that overlook the reception area are a must-see, among them the Hall of Honor, the largest room in the fortress used for ceremonies and banquets, and the Camera Pinta, featuring two beautiful and well preserved cycles of profane frescoes dating back to the 14th and 15th centuries.

Fifteen rooms inside the fortress host the National Museum of the Duchy of Spoleto, inaugurated in August 2007 after the full restoration of the internal rooms.
The works and artefacts are displayed according to a chronological order and witness the artistic vitality and cultural unity of the vast territory of the Duchy of Spoleto, in the historical period that goes from between the 4th and 15th centuries AD.

The museum also houses a collection of artifacts dating back to the 4th -5th century AD that come from funerary sites  nd religious buildings. These objects bear witness to the development of the first Christian communities in the area and to the phenomenon of monasticism, which was widespread throughout the mountains around Spoleto.

The precious early medieval works show the great political and cultural importance of Spoleto as capital of one of the most important Lombard duchies in the Italian peninsula.
The section dedicated to the grave goods, coming from the necropolis of Nocera Umbra is of great artistic importance and displays life and social organization of the Langobards.
The second section of the museum houses a large number of valuable sculptures and paintings, dating back both to the Romanesque period and to the Renaissance. Signage in the museum provide historical information about the exhibits.