The city was founded, or better fortified, during the medieval wars between the Lombards and the Byzantine Empire; the name comes from a more ancient fortress called "Sassonion" or "Saxonion", so the "Castron" appeared in some documents as "Neon Sassonion", likely the ancient Byzantine name corresponding to the medieval Latin "Castrum Villarum". Officially the city entered the history in 1064 AD when the "Castra" was occupied by Norman warriors led by Robert Guiscard. In 1090, during the county of his son Roger Borsa, the sanctuary of "Saint Mary of the Castle" Madonna del Castello was built.