Castelli Romani ( Roman Castles)
With the name of Castelli Romani it indicates a set of towns or cities of the Alban Hills located a short distance from Rome, in part of the territory of the Lazio Vetus. As the historian Giuseppe Tomassetti (1848-1911) reconstructed, the denomination dates back to the 14th century when many inhabitants of Rome, to escape the economic and political difficulties deriving from the Avignon Captivity, took refuge in the castles of the Roman feudal families of the Savellis (Albano and Castel Savello, Ariccia, Castel Gandolfo, Rocca Priora), the Annibaldi (Molara, Monte Compatri, Rocca di Papa), the Orsini (Marino) and the Colonna (Monte Porzio Catone, Nemi, Colonna, Genzano and Civita Lavinia)
The territory of the Roman Castles is an area of volcanic nature, originating from the collapse of the Latium Volcano some hundreds of thousands of years ago. The main mouth of the Latium Volcano occupied the entire area of the internal belt of the Castles: it later collapsed, giving rise to various secondary vents, the most important of which was the present Monte Cavo (949 m asl). The other minor mouths of the Volcano have become lake basins between 100,000 and 20,000 years ago, and for the most part have been drained over the centuries.
According to the classification given by the Geological Survey of Italy most of the territory of the Roman Castles is composed of soils classified as v2 , that is, final eruptive material that gave rise to the famous peperino. The most famous quarrying areas of peperino are in Marino, in Albano, in Ariccia and in some areas of the Latina Valley.
Seismic classification: zone 2 (medium-high seismicity), Seismic reclassification of the territory of the Lazio Region 2003
The Castles can be subdivided into different sub-areas: the tuscolana area (Colonna, Frascati, Grottaferrata, Monte Porzio Catone, Monte Compatri, Rocca di Papa, Rocca Priora) pivoting on Frascati, the appia or albana area (Albano Laziale, Ariccia and Castel Gandolfo) pivoting on Albano Laziale and the Lanuvina area (Lanuvio, Genzano di Roma, Nemi), which is pivotally named Lanuvio but actually on Genzano di Roma. Velletri and Lariano, which we might call the Artemisia area, are a separate area, as is Marino, which represents the link between the Tuscan-Alban area.
A heated debate is still ongoing on the exact determination of the boundaries of the Roman Castles. Elio Migliorini  lists fourteen municipalities including also the two localities of Colonna and Lanuvio, indicating them as peripheral extremities that already present elements of separation; Lidia Piccioni also lists fourteen municipalities. Both authors exclude Velletri, who nevertheless shares some of the prerogatives of the Castelli family, despite having a substantially different history. Armando Ravaglioli  instead lists thirteen municipalities also mentioning Velletri and Lanuvio for the contemporary tendency to include them.
However, the “historic” municipalities of the Castelli Romani are fourteen: Albano Laziale, Ariccia ,Castel Gandolfo ,Colonna,Frascati ,Genzano di Roma Grottaferrata ,Lanuvio ,Marino ,Monte Compatri ,Monte Porzio Catone ,Nemi ,Rocca di Papa ,Rocca Priora
In addition to these fourteen, there are two others that are considered to be part of the Castelli Romani Lariano and Velletri