Sarno, of extremely ancient origin, takes its name from the mountain that towers above it. Archaeological excavations have unearthed settlements that date from the ancient Bronze Age, the Iron Age and the Roman Hellenistic era, up to the construction of the countship, ruins of its medieval castle, still visible today, and settlements of Suevian, Angevin and Aragonese times.
The castle was built in 758-786 A.C. at the request of the Lombard Arechi II, Prince of Benevento, and constituted a reinforcement in the military defences of the Sarno valley against the frequent Byzantine incursions of the Duchy of Naples.
The castle was demolished at the end of the fifteenth century following the famous Baron conspiracy, hatched by the count Francesco Coppola.
From the underlying land rose the first inhabited zone of Sarno itself, in that period one of the 33 “gastaldi” (land owned by the chamberlain) in which the southern Lombardy was subdivided.
With the accession of the Medici family that ruled between 1690-1806, the countship became a Duchy. During contemporary times, this region, thanks to the abundance of water, became important in the hemp industry, that was given a further substantial boost in 1856 with the arrival of the railway.