In 357 A.D., Pope Liberius sent to the Eastern bishops the apostolic
letter STUDENS PACI translated here: (DS 138):
“Working for the peace and concord of Churches, after having
received the letter, of your charities on behalf of Julien, bishop
of happy memory, in relation to Athanasius and others, I have
sent according to the traditions of “a latere” to Alexandiria,
the priests of the city of Rome, Lucius, Paulus and Helianus,
to the aforesaid Athanasius in order that he should come to Rome
so that what befalls the discipline of the Church may be now decided
about him.
“Moreover, I have sent him a letter by the aforesaid priests in
which letter it was made clear that if he did not come he would
be stranger to the communion of the Roman Church. These priests
having therefore returned announced that he did not want to come.
“So, from the letter which of your charity you wrote to us about
the said Athanasius, by this letter which I write for your concord,
that I may have peace myself with you all and with all the bishops
of the Catholic Church, know that the said Athanasius is a stranger
to my Communion and to that of the Roman Church and to the participation
in letters and ecclesiastical matters.”
Ever since, historians, theologians, and canonists of all types,
without themselves ever questioning the orthodoxy of the excommunicated
(canonised) never cease to question that of the excommunicating
pope…. (Fideliter, No 69, p. 20)