 With Charlemagne's conquest of northern Italy in 773, San Severino swore loyalty to Pope Adrian I, following the entire region of Pentapolis.The first reliable document concerning the existence of this new centre dates back to 944, year of foundation of a larger church to accommodate the faithful and the relics of Saint Severino that was placed in the hamlet of the "Castellum Severinum Sanctum".Documents from the 11th and 12th centuries show that the Castle of San Severino was part of the diocese and the Camerino March before being transferred in 1119 to the Marquis Werner II of Spoleto, who had come from Germany to fight for the Pope against the Normans.