The origins of the Castello di Arechi II in Salerno are deeply rooted in history, with some sources tracing its beginnings back to the Roman era. Indeed, around the 2nd century B.C., Rome, recognizing the strategic significance of Salerno, which was already one of its colonies, decided to fortify the city atop Mount Bonadies. This mountain's elevated position provided exceptional defensive advantages, commanding a sweeping view of the entire Gulf. The Bonadies, often referred to as the "Mountain of Good Morning," owed its name to the fact that the rising sun, emerging from the east, first illuminated its summit. This peak, soaring 300 meters above sea level, represents the highest point of the ancient city, founded by the Romans on the slopes of this mountain in 197 B.C. The actual construction of the castle is believed to have taken place around the 6th century A.D., during the Greco-Gothic War. This conflict pitted the Ostrogoths, who had conquered Italy, against the Byzantines, who sought to reclaim territories lost in the Western Roman Empire following the fall of Rome in 476 A.D. The castle is said to have been built under the direction of the Byzantine general Narses. Indeed, some remnants of the Byzantine fortification are recognizable in the original structure of the castle, notably in certain sections featuring square masonry. During the 7th century A.D., the Lombards ruled over Salerno, and the castle became an integral part of the city's landscape. In 774 A.D., Prince Arechis II of Benevento made the decision to relocate his court to Salerno and construct his personal palace by the sea. The prince chose to build his residence in the heart of the ancient city, where he resided until his death. Concurrently, the castle assumed a pivotal role in the newly developed defensive system. Arechis elevated and modified the walls of Salernum, transforming the castle into the apex of a triangular defensive network. The city walls extended from the castle down the slopes of Mount Bonadies to the sea, effectively enclosing and safeguarding the city from all angles. Consequently, Arechis II not only reinforced the preexisting fortification but also integrated it into a defensive system that rendered the castle nearly impregnable.