Salerno as "oppidum" was founded by Romans in 194 BC. After 660 years, with the fall of the Western Roman Empire, Salerno remained an important stronghold under the Ostrogoth domination of Italy but was affected by the general decline in which it found itself.
What the landscape of southern Italy must have been like after the disasters of the Greco-Gothic war (535-553 AD), fought right on the plain between Salerno and Sarno, is widely known. The contraction in the number of inhabitants, also due to the incidence of epidemics, the abandonment of the main Roman roads and the neglect of crops, certainly could not guarantee a rapid recovery of the economy.Salerno in the Christian era was exposed to the barbarian invasions that penetrated into Campania and, particularly disputed for the port. Invaded and semi-destroyed by the barbarian populations who came down from the North, the city of Salerno fell in 476 AD under the name of Odoacer (Hun), and in 493 AD under the name of Theodoric (Ostrogoth).
Odoacer, after having deposed the last emperor Romulus Augustus in 476 AD and having exiled him to a luxurious villa in Salerno with a notable prerogative, claimed to govern Italy in spite of the Eastern Roman emperor Zeno, who, to bring the peninsula back under his power, initially supported the Ostrogoths led by Theodoric encouraging them to invade Italy to free it from the presence of Odoacer.
The year 536 is often cited as the worst in history. A massive volcanic eruption (presumably in Iceland) caused low temperatures and darkness across Europe, the Middle East, and parts of Asia. The lack of sunlight affected the crops, leading to famine. The Roman Empire had just fallen, so things were truly chaotic.
The Justinian plague was also brutally devastating. It is estimated that about 25-50 million people died between 541 and 542. At that time, this accounted for about a quarter of the world's population. And many of those who were not killed by it eventually died of hunger, as the prices of grain rose enormously due to the plague.
Occupied for the first time in 526 AD during the Greek-Gothic war, the city fell in 542 AD under the Goths led by Totila, but after his death in the battle of Tagina, Salerno again passed under the Byzantine power, and remained there until 646 AD, year in which it was incorporated into the Lombard Duchy of Benevento.
In 555 AD the last Gothic troops surrendered in the Compsa (Conza della Campania) fortress, north-east of Salerno.