Pavia obtained it through the intervention of emperor Frederick II. Later it was under the Visconti (who gave it as a fief to Alberico da Barbiano together with Belgioioso) and the Sforza of Milan.
Pavia's ownership changed hands due to the intervention of Emperor Frederick II, with subsequent transfers to the Visconti family, who granted it as a fief to Alberico da Barbiano, and finally to the Sforza of Milan.