The Bull “Commissa Nobis” of Pope Callixtus II (1123) reports, almost verbatim, a previous Bull of Pope Paschal II (1113), telling us that the Church of Carpi was founded by the Lombard King Astolfo. The commonly accepted year of foundation is 751. The two Bulls confirm the privileges of autonomy of the Pieve of Carpi, which was not to be dependent on any Bishop, but immediately subject to the Holy See. Since, according to some, the evidentiary force of these Bulls for the centuries before was not solid, the historians of Reggio, who considered the Carpi area to be the territory of the Diocese of Reggio, contested and even denied the autonomy of the Church of Carpi in those distant times, before the year 1000. The matter was clarified later and the privileges of independence were explicitly recognised by subsequent Bulls of Pope St. Gregory VII (who was in Carpi in March 1077) and by Pope Urban II.
