This is from the Former Archbishop Lazar's site, (he apparently venerates the First Hierarch of ROCOR as a Saint, so please don't be snadalized.), where is a letter of Metropolitan Anthony of ROCOR speaks about the New Calendar. He lived while the years of the change in Greece.
Also, before he became the president of ROCOR, he was Metropolitan of Ukraine Kiev. According to Lazar, he is called "Saint Antony of Kiev."
http://orthodoxcanada.org/102004/saintantony.html
WORKS OF ST ANTONY OF KIEV
LETTERS OF ST. ANTONY KHRAPOVITSKY TO THE MONK THEODOSY ON MOUNT ATHOS.
That the change of the Calendar does not constitute a heresy or a cause to break communion with the hierarchs who use the "new calendar." On the near impossibility of having a valid Pan-Orthodox Council.
12 October, 1926
Honoured and beloved Batiushka Fr Theodosy!
Today I read your letter with love and praise for your zealousness. Truly, one or perhaps two of your writings were lost in the post, so that only from today's letter did I come to understand that you are troubled precisely about the calendar.
I reply to the question directly placed by you. For, as is well known to you, Canons 13, 14, 15 of the First and Second Council speak of separating oneself from a bishop or patriarch after his condemnation by a council, but not by the personal judgment of the one who is separating himself. That Canon (15) which states that a clergyman is worthy not of condemnation, but praise, who ceases a union with him [a hierarch] due to some heresy condemned by the holy councils or the fathers ...."When he preaches a heresy publicly and teaches it openly in the church." But this, glory to God, neither Patriarch Vasilios, nor Chrysostom[1] have not done yet. To the contrary, they insist on the preservation of the established Paschalion, since only it, and not the Julian [calendar] style itself, is guarded by the anathema of the councils. It is true that Patriarch Jeremiah[2] in the 15th century and his successor in the 1800s placed an anathema on the style itself.[3] This condemnation, however, (1) concerns only their contemporaries and (2) does not spread to [i.e. condemn] those who do not threaten to cease communion with him [that is, the hierarchs who have switched to the new calendar] to which only the abusers of the canonical Paschalion are subjected.[4] Moreover (this must be noted in any case) the main concern about the day of Pascha is contained [in the declaration] that it be celebrated on one and the same day in the entire universe by all Christians (i.e. Orthodox Christian). It is true that my co-brethren and I are in no way sympathetic to the new style and to modernism, but we ask the Athonite fathers not to rush with the writing of an epistle (Romans Ch. 14).[5]
Concerning our readiness to go to a Constantinople Council,[6] do not grieve. Of course, there will be no council but even if there would be, and if we go, then as St Flavian who had found himself at a robber-council, we shall preserve the truth, while the apostates we will subject to an anathema. But, until such time as they have not said the last word, until all the Church at an ecumenical council has repeated the anathema of Patriarch Jeremiah, one must keep aloof ...., so that we ourselves are not deprived of salvation, and while straining out a mosquito, we do not swallow a camel.
I ask you, holy father, for your prayers. You yourself know that it is sorrowful amongst us. Your well-wisher,
Metropolitan Antony
P.S. Today I found out about the sudden death and place of burial of my last brother Alexander (7 September). Pray for his soul.
[1]. Vasilios II, Patriarch of Constantinople, ascended the throne in 1925. Archbishop Chrysostom (Papadopoulos), introduced the new style in the Greek Church in March, 1924.
[2]. In 1583 Gregory XIII, Pope of Rome, who had changed the Julian Calendar (old-style) to the Gregorian (new-style), invited Jeremiah II, Patriarch of Constantinople, to follow his example. In reply to this in that same year, there was convened in Constantinople a council of Orthodox hierarchs at which attended the patriarchs: Jeremiah II of Constantinople; Silvester of Alexandria; Sophronios of Jerusalem and many other bishops. They anathematized the change of the paschalion and in general the new style: "...to whomever follows the newly created Paschalion and the new calendar of the Godless papists astronomers....anathema, and let them be excommunicated from the Church and from the gathering of the faithful." In his letter, Metropolitan Antony erroneously wrote "the 15th century," where he intended to say "the 1500s.".
[3]. In 1848 there was formed the decree of the four eastern patriarchs: Anthimos of Constantinople, hierarchs of Alexandria, Methodios of Antioch and Cyril of Jerusalem and 18 other bishops which affirmed the decree of the 1583 Constantinople Council concerning the new style. other bishops which affirmed the decree of the 1583 Constantinople Council concerning the new style.
[4]. Thew thought here is that no one is anathematised for not having broken communion with the hierarchs who introduced the New Calendar, so long as they did not attempt to change the Paschalion.
[5]. The Saint is advising the Athonite monks not to hasten to write an epistle of condemnation about the use of the New Calendar, or of the hierarchs who introduced it.
[6]. At that time preparations were taking place for the convening of an Eighth Ecumenical Council in Constantinople. The council which did not take place threatened to be severely reforming.