For all the stated reasons, the Catholic Eastern Church severed its communion with the local Church of Rome, which had fallen away from the truth and from the canons of the catholic Orthodox Church. Just as The Roman bishops had begun with pridefulness, they are also ending with pridefulness. They are intensifying their argument that allegedly the Orthodox Catholic Church fell away from their local Church. But that is wrong and even ridiculous. Truth testifies that the Roman Church fell away from the Orthodox Church. Although for the sake of imaginary rightness papists promote the view that during the time of union with the Catholic Orthodox Church, their patriarch was first and senior among the five patriarchs, this was true only for the sake of Imperial Rome, and not because of some spiritual merit or authority over the other patriarchs. It is wrong that they called their Church “Catholic”, i.e. universal. A part can never be named the whole; the Roman Church before its fall from Orthodoxy, comprised only a fifth part of the one Catholic Church. Especially since it rejected the decisions of the Ecumenical Councils the Roman Church should not be called catholic, as it follows its own incorrect theorizing.
+ St. Ambrose of Optina, A Reply to One Well Disposed Towards the Latin Church
Regarding the unjust glorying of the papists in the imaginary dignity of their Church