The political changes of the ninth and tenth centuries favoured the revival of the Lombard See. With the disruption of Charlemagne’s swollen empire, and the removal of the temporal support, the spiritual sovereignty of Rome and the unity of the Church broke down, at least in practice, and the grand and comprehensive idea of a single rule of Christendom under the twin sceptres of Emperor and Pope—that inspiration of great minds in the Middle Ages—failed now, as later, of realisation. Amid the ungoverned turbulence of the Roman nobles and citizens the Papacy gradually sank to the lowest depths of corruption and impotence, and any deference to its authority once paid by the Milanese primates was soon forgotten.
For a while the Carlovingian kingdom of Italy held together in spite of constant wars, and under Louis II. Lombardy enjoyed a period of peace and great prosperity. But after his death in 875, the country, rent by the struggles of various claimants to the throne, and overrun by Huns and Saracens, was gradually reduced to a state of chaos, out of which the power of the feudal barons emerged as the only effective authority. The Counts and Viscounts, as the imperial ministers were properly called, lost their authority, or else preserved it as an hereditary and almost independent right from father to son, fitting themselves as time went on into the graduated order of the feudal system, which was extending itself into the whole organisation of society. The one stable power, that of the Church, based on an inextinguishable tradition, became paramount in the city, and in virtue of its vast possessions assumed the temporal as well as the spiritual dominion. By the tenth century the Archbishops of Milan appear as great feudal princes, the most powerful in North Italy, and practically independent of the Emperor. This position was largely due to the spirit and ability of the two great prelates of the previous century, Angilberto (824-59), and Ansperto (868-81). Ansperto openly refused the obedience claimed from him by John VIII. By assembling and presiding over the Diet of the princes of North Italy at Pavia, which elected Charles the Bald as successor to Louis II., and afterwards crowning the new monarch, he arrogated the right of conferring the Crown of Italy independently of the Papal approval. He appears in this election as a great temporal prince, leading the North Italian States, and expressing the revolt of Lombardy against the pretensions of the Pope in the Lateran to the heritage of the power which once dominated the world from the Capitol. Throughout the struggles of the next twenty years for the possession of the throne, Ansperto’s support was always given in opposition to the Pope. When summoned by John VIII. to a Council at Rome in 879, to answer for his offences against the Holy See, he shut the door against the papal legates, so that they were compelled to the undignified proceeding of shouting the pontiff’s complaint through the keyhole; and he and all his vast flock, which included, with the suffragan Sees, the whole of Lombardy, were totally indifferent to the excommunication stammered against them by the enraged and helpless Pope.