In January 756, however, Aistulf, mad from the start, laid siege to Rome, and for three months laid waste the farms of the Campagna, S. Peter’s patrimony.  Narni was taken and indeed all seemed as hopeless as ever.  Then the pope took up his pen and as the successor of the Prince of the Apostles wrote a letter as from S. Peter himself and sent it to the three kings, Pepin, Charles, and Carloman, to the bishops, abbots, priests and monks, the dukes, counts, armies, and people of Francia.  Gibbon thus summarises this extraordinary and dramatic epistle:  “The apostle assures his adoptive sons the king, the clergy, and the nobles of France that dead in the flesh, he is still alive in the spirit; that they now hear and must obey the voice of the founder and guardian of the Roman Church; that the Virgin, the angels, the saints, and the martyrs, and all the host of heaven unanimously urge the request, and will confess the obligation; that riches, victory, and paradise will crown their pious enterprise; and that eternal damnation will be the penalty of their neglect, if they suffer his tomb, his temple, and his people to fall into the hands of the perfidious Lombards.”

Pepin could not be deaf to such an appeal.  He again crossed the Mont Cenis, and again the Lombards were as chaff before him.  On his march to Pavia he was met by two envoys from Constantinople who had ill-treated, detained, and outstripped the papal ambassador.  They besought Pepin to restore Ravenna and the exarchate to the empire, but he denied them and declared roundly that “on no account whatsoever should those cities be alienated from the power of the blessed Peter and the jurisdiction of the Roman Church and the Apostolic See, affirming too with an oath that for no man’s favour had he given himself once again to this conflict, but only for love of S. Peter and for the pardon of his sins; asserting, also, that no abundance of treasure would bribe him to take away what he had once offered for S. Peter’s acceptance."[1]

[Footnote 1:  Cf.  Hodgkin, op, cit. vii. p. 217.]

Pepin marched on; Pavia was besieged, Aistulf was beaten to the dust.  A treaty was drawn up in which the Lombard gave to “S.  Peter, the Holy Roman Church, and all the popes of the Apostolic See forever” the Exarchate, the Pentapolis, and Comacchio.  An officer was commissioned to receive the submission of every city, and their keys and the deed of Pepin’s donation were placed upon the tomb of S. Peter in Rome.  The papal state was founded; where the empire had ruled so long there appeared the heir of the empire, the papacy “sitting crowned upon the grave thereof.”