The Castle of Rocca Sinibalda was built over a previous fortress (possibly a Lombard castle) by Cardinal Alessandro Cesarini in the 16th century. The initial project was the work of famous architect Baldassarre Peruzzi from Siena in 1530, who died six years later.

The castle was likely completed by Peruzzi’s son Giovanni Sallustio and Bartolomeo De Rocchi. The castle was situated on the border of the Papal State and the Kingdom of the Two Sicilies, and Peruzzi’s intention was to adapt the castle’s original plan and shape it into what has been either interpreted as an eagle or as a scorpion-shaped fortress—something rather exceptional among European castles from the time.