For the next sixty years the history of Europe is that of Carolingian conquests and essays in political reconstruction. And now the growing connection with the Papacy acquired a new character. Since the beginning of the eighth century the Eastern Empire had forfeited the last claim to Italian allegiance by embracing the Iconoclastic heresy, a protest at once belated and premature against the growing materialism and polytheism of Catholic Christianity. Pope and Lombards made common cause to protect the images in imperial Italy. Gregory III excommunicated the iconoclasts (731); the Lombard King Aistulf seized Ravenna, the last important stronghold of the Byzantines in the peninsula (751). Too late the Papacy realised that the orthodox Lombard was a greater menace than the Greek heretic. Aistulf regarded Rome, in common with the other territories of the Empire, as his rightful spoil. For the first time the issue was raised between secular statesmanship scheming for Italian unity and a Roman bishop claiming sovereign power as the historical and indispensable adjunct of his office. Pope Stephen II visited the Frankish court to urge, not in vain, the claims of religion and of gratitude. By two raids across the Alps Pepin forced the Lombard to withdraw the claim on Rome, and furthermore to restore what had been conquered from the Empire. These territories, lying in Romagna and the Marches, the Frankish King conferred on the Pope, as the legitimate representative of imperial power (756). Pepin's Donation, made in defiance of Byzantine protests, greatly extended the temporal power which the predecessors of Stephen had long exercised in Rome and the neighbourhood. A shrewd expedient for crippling the most formidable rival of the Franks, it was to be the rock on which ideals then undreamed of were to founder. For it was the temporal power which provoked the last and mortal struggle of the Holy Roman Empire with the Papacy, which presented the most stubborn obstacle to the leaders of the _Risorgimento_.