Casalvieri is located on a small hill in Val Comino at the foot of Mount Cairo and through its territory flows the charming river Melfa before joining the Liri River.
Casalvieri and the Comino Valley have been inhabited since the Palaeolithic age, and the first population to have this role were the Volsci, of which little is known, and then the Samnites took over in the eighth century BC. The Samnites were skillful and daring warriors and fought hard against the advancement of the Romans with whom they clashed for the first time in the Samnite War in 354 BC. The Romans fought another two before they could expand into southern Italy and the 3rd Samnite War was fought in Val Comino.
Probably the name of Casalvieri comes from ‘Domus Olivieri’ and therefore has Roman origins, perhaps of a villa in the area.
The creation of the medieval village occurred around the thousand when the people of the Val Comino sought shelter in the hills to escape the Saracen invasions by building castrums, which then turned into castles. The first citation about the castle dates back to 1017.
In the Middle Ages Casalvieri was first part of the Duchy of Benevento and then of the Principality of Salerno.
In 1076 it is known that this castle belonged to the Abbey but for its strategic position Casalvieri has had many changes of ownership. It was the fiefdom of the lords of Aquino and part of the county of Arpino.
In the sixteenth century it was ruled by the Della Rovere family and, from 1580 until 1796, by the Boncompagni.
In the Bourbon period it was part of the Terra di Lavoro province and, just as many of these lands that later passed to the Kingdom of Italy, experienced the phenomenon of brigandage and of those who opposed the new order.
After the unification of Italy and after the two world wars, in particular the second, which had the front of German resistance, the Gustav Line, in this valley, Casalvieri lost many through emigration but they still maintain strong ties with this splendid territory.