The villa and its gardens are located on Augustan-age terraced structures (antique temple foundations) which in turn were erected on a cult area dating back to the 4th century BCE. The history of Villa Fidelia began in the second half of the 16th century, when the Acuti Urbani counts of Spello decided to build their stately residence here. A second phase of radical transformation took place in the 18th century, when Princess Teresa Pamphili Grillo acquired the property. Legend has it she stopped in Spello attracted by the beauty of the place while travelling to forget her unhappy marriage. The transformation of the villa led to the creation of the Italian-style formal garden on the highest Roman substructure, bordered by walls with niches and fountains below a holm oak park. The villa underwent further transformations in the first decades of the 19th century when it was acquired by Gregorio Piermarini: the casino built between 1805 and 1830 (calledCasino di villeggiatura, a small holiday residence) was perhaps designed by the famous and homonymous architect Giuseppe Piermarini (and then renovated in 1931 by Cesare Bazzani with an eclectic taste blending Baroque and Neoclassical features). A highly scenic garden (the Giardino Vesuviano, Vesuvian Garden) was also created, and the Italian-style garden was further enriched. Eventually in 1923 the villa was purchased by the engineer Decio Costanzi, who divided the property selling the gardens and its outbuildings to the Province of Perugia. Both the Giardino Vesuviano and the Italian-style garden, while maintaining their previous layout, were renovated and their scenic value enhanced. In 1930, when the work had just been completed, Villa Fidelia became the setting for a lavish wedding reception between Giovanna di Savoia, daughter of Vittorio Emanuele III, and Boris III of Bulgaria, who were married in Assisi.