The result of their interview is given in the Liber Pontificalis: "The most blessed pope tearfully besought the said most Christian king that by means of a treaty of peace (? with him the pope) he would dispose of the cause of the blessed Peter and the republic of the Romans, who by an oath there and then (de praesenti) satisfied the most blessed pope that he would obey all his commands and admonitions with all his strength and that it pleased him to restore by every means the exarchate of Ravenna and the rights and territories of the republic."[1]
[Footnote 1: As this is very important I give the original Latin "Ibidem beatissmus Papa praefatum Christianissimum regem lacrimabiliter deprecatus est ut per pacis foedera causam beati Petri et reipublicarae Romanorum disponeret. Qui de praesenti jurejurando eundem beatissimum Papam satisfecit omnibus ejus mandatis et ammonitionibus sese totis nisibus obedire, et ut illi placitum fuerit Exarchatum Ravennae et reipublicae jura seu loca reddere modis omnibus.">[
That winter the pope spent at S. Denis, where he solemnly crowned Pepin and his queen, and Charles and Carloman their children, pronouncing an anathema upon all or any who should ever attempt to elect a king not of their house. Upon Pepin too he conferred the title of patrician. Can it be that by this he intended the king of the Franks to be his executor in the exarchate as the exarch had been the executor of the emperor?[1] We do not know; but a little later a document was drawn up in which Pepin declared and enumerated the territories he was ready to secure for the pope. This document, the Donation of Pepin, would seem to have confirmed in detail and in writing the oath he had sworn to the pope at Ponthion. Unhappily the document has disappeared, and we can only judge of its contents by what actually happened.
[Footnote 1: The title patrician was not exclusively borne by the exarch, the Dux Romae, for instance, bore that title in 743.]
The adventure into Italy to which the pope had persuaded Pepin was not universally popular with the Frankish nobles. We find Pepin attempting to gain his end by negotiation with Aistulf, but all to no purpose, and probably in March 755 the Franks set out with the pope at their head to march into Italy to curb and chastise the Lombard.
The great army of Pepin crossed the Alps by the Mont Cenis, and in what was little more than a skirmish upon the northern side of the pass defeated the Lombard army and proceeded to invest Pavia and ravish the country round about. Aistulf, who was rather an impetuous than a great soldier, had soon had enough and was ready to entertain proposals for peace. A treaty was made in which he agreed "to restore" Ravenna and divers other cities, and to attempt nothing in the future against Rome and the Holy See. This having been decided, the pope took leave of Pepin, who returned to France, and went on his way to Rome.
The pope had won and had really established the Holy See as the heir of the empire; but Aistulf was by no means done with. He forgot alike his treaty and his promises. "Ever since the day when we parted," the pope writes to Pepin and the young kings, his sons Charles and Carloman, "he has striven to put upon us such afflictions and on the Holy Church of God such insults as the tongue of man cannot declare…. You have made peace too easily, you have taken no sufficient security for the fulfilment of the promises you have made to S. Peter, which you yourselves guaranteed by writing under your hand and seal…."
But the Franks were deaf. An expedition to crush the Lombards was a laborious and an expensive business, and Pepin had much to occupy him at home.
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]