From the Serra you can reach the stronghold Castle built in the 8th century. It is said to be of S.Adiutore because on this hill it is believed there was the cell where the Holy Bishop retired, in the fifth century, even if some historians maintain that it was built in an earlier period for its function of fortification of the roads that they crossed the valley to protect the people.
The date of construction of the Castle is uncertain: some scholars date it to around 787; others instead around the IX -X century. In fact, some historical references state that it was wanted by the Lombards and precisely by Arechi II, prince of Benevento, who had it built in 773 to fortify his Duchy against a possible attack by Charlemagne, who had sworn to eliminate the Lombards from 'Italy and therefore Arechi decided to move to Salerno by building, in addition to the Castle above Salerno, four other castles as outposts against attacks from the hinterland. Being very religious, he entitled the castles to Saints (S.Severino the one to the East, S. Giorgio the one more to the left, S.Adiutore a Cava and Nocera which was called apud montem). Other references have it that the Castle was built later, in the 9th century to defend the Saracens, who had landed in Cetara and on the opposite coasts of the Gulf of Salerno. However, it is certain that the castle was donated by Duke Ruggiero to his son Roberto, son of the Norman Algerico, towards the end of the 11th century.
In 1110 it was purchased by the Monastery of the S.S. Trinity for 1,010 disgusted: it was inhabited by a monk and a layman who commanded the garrisons who lived on the castle.The monastery then lost possession of the castle of S.Adiutore in 1291 when it was destroyed by Robert Count of Arras, vicar of King Charles II of Anjou. Rebuilt in 1380 (for this reason a gabelle was imposed on Cavesi), the castle became a military post until 1943, when it was occupied by the Germans who, due to their position, placed batteries of cannons that kept the road under fire for about 20 days. between Vietri and Cava, delaying the advance of the allied troops landed in Salerno. when the decay of the structure began, following the German bombing during the Second World War. In 1970 the municipal administration restored the site and a plaque was placed in memory of this.
The fortress was damaged in September 1943 and was completely restored in 1970.
There is no shortage of legends: somewhere there should be an underground and secret passage between the Castle of Cava and that of Salerno; in the cistern of the Castle an old witch has died and reappears every now and then; a treasure should be hidden in the Castle or along its flanks.