Back in the 1850s, Cardinal Wiseman had a falling-out with his Coadjutor, Archbishop Errington. For these purposes, we do not need to know much about why, nor to speculate on the involvement of Henry Manning.
The plain fact was that Wiseman and Errington could not work together, and Errington made little effort to conceal the fact. The matter went to Rome, where Mgr Talbot, not one of our heroes, exacerbated matters by accusing Errington of Gallicanism. It is perhaps fair to say that Errington was out of sync with the current style of Catholicism represented by Pio Nono, Wiseman, and Manning. It sometimes can happen that a bishop may be out of sympathy with the Roman Pontiff ... or even vice versa.
Errington went to Rome and, of course, was received by the Pope. It is, surely, well-nigh inconceivable that a bishop whose job was in question should not be welcomed fraternally and paternally and sympathetically in Rome by the Sovereign Pontiff. Pio Nono begged Errington, as a personal favour to himself, to resign his coadjutorship and to accept the Archbishopric of Port of Spain. Errington refused to resign, but made clear that he would obediently leave his job if the Pope so ordered him. Papa il conte Mastai-Ferretti was unwilling to take such extreme action; and again implored Errington to accept the post offerred him in Trinidad. It was made clear that Talbot's slanders were not believed. Errington took out a pocket book and started to transcribe the Pope's words, which was a novel experience for the Pontiff. Matters deteriorated; soon the guards and the prelates in the ante-chamber were surprised to hear, from behind the closed doors, the two hierarchs shouting angrily at each other.
Errington stormed out of Rome crying Vim patior; patior iniustitiam. The Holy Father felt he had no alternative but to relieve him of his Coadjutorship; upset by the uniqueness of the action to which he was driven, Pope Pius referred to it as Il colpo di stato di Dominiddio. Brian Fothergill, the author (2013) of a biography of Wiseman, quotes a description of it as "an exercise of [the pope's] supreme authority and an exertion of power altogether unwonted and perhaps unprecedented".
Of course, Blessed Pio Nono was an ultramontane tyrant; a baroque throw-back to the unhappy days of Renaissance absolutism. Everybody knows that. Equally, everybody knows how inconceivable it is that, in our happier age, a pope would dismiss or constructively dismiss a bishop for anything other than the very gravest doctrinal or moral delinquency. Deo gratias.