Characterized by an irregular pentagon shape, the fortress was built on the remains of an Etruscan acropolis, which is visible on part of the wall, and consists of a triangular tower high. 39m and four towers that strengthen the crenellated walls. Two of these were built in the first half of the XVI century, they are circular in shape, in that the round structure was more resistant to attacks with cannons.
The words “Lion Rock”, with which often is referred to this architectural complex is not attested in any documents of the time or later.
In the acts of the Municipality of Perugia in the second half of the XIII century, when construction begins, this is always defined as Rocca.
The medieval fort has represented for the Municipality of Perugia the strategic control of the area of the Trasimeno and Chiugi.
Testimony of its importance and of the close economic relationship, that elapsed between the city and the territory are the sculptural decorations present on the Fontana Maggiore of Perugia, made by Nicola and Giovanni Pisano in 1278.
On either side of the statue of Augusta Perusia, enjoying a prime location pictures of Domina Laci ferens pisces, the “Lady of the Lake leading fish” and Domina Clusii ferens Granum, the “Lady of Chiugi leading grain”.
Inside the fortress they are preserved the ruins of a church of Byzantine origins probably, dedicated to Saints Philip and James, probably built on the remains of an Etruscan temple.