Dear Griego Amigo,
You always do such comprehensive research on things!
In fact, the several Feasts in the UGCC calendar that were taken from the West - Corpus Christi, Jesus, the Lover of Mankind (aka the Sacred Heart), the Sorrowful Mother/Compassion, Christ the King and the Immaculate Conception - are not mandatory in terms of their observance.
In my neck of the woods, there are parishes that observe them or some of them, and others who do not, seeing them as Latinizations which, of course, they are.
In 1904 at the time of the establishment of the Russian Catholic Church (aka "Russian Orthodox in communion with Rome"), the issue of the Sacred Heart devotion in June was raised. Rome decided in favour of the more Easternized "Jesus, the Lover of Mankind" although at least one such parish adopted the full Western style of this devotion as obtained in the UGCC at the time and there is an Akathist to the Sacred Heart by Fr. Isidore Dolnitsky and other similar devotions adapted to a Byzantine liturgical framework (how successfully is not for me to judge as that is just not my forte). The Ven. Metropolitan Andrew Sheptytsky, the impetus behind the Russian Catholic Church, actually dedicated the project to the Sacred Heart of Jesus.
In fact, St Nicholas Cabasilas in his commentary on the Divine Liturgy makes mention of the "Heart of Christ." An Orthodox commentator said that the Orthodox Church honours the "Heart of Christ" and that this is different from the Western, 'pietistic' devotion to the Sacred Heart of Jesus etc.
At the same time, Ukrainian Orthodox in western Ukraine began to pick up some of these feast days and devotions, especially the feast of the Sorrowful Mother of God/Compassion for which some Orthodox parishes used EC liturgical texts which were otherwise placed under lock and key for the interim (there was a monograph on this published in Chicago but I've lost it and don't remember who wrote it).
Certainly, when the UGCC was forcibly reunited to the ROC in 1946, former EC parishes continued to celebrate these feasts (one Ukrainian priest once had an ROC prayerbook published in western Ukraine - during the Soviet era - which actually had the service of Supplication for Eucharistic Benediction!).
In fact, during the era of the Kyivan Baroque, very many Western devotions were adopted wholesale by Orthodox saints such as St Dmitri (Tuptalenko), St Peter Mohyla and others including the saying of a Hail Mary at the turn of every hour, night and day, the Western form of the Rosary, the Little Office of the Blessed Virgin Mary, the 15 Prayers of St Brigitte, forms of the Way of the Cross (especially loved by St Tikhon of Zadonsk who had life-size "stations" placed in his cell) and others. The service of the Passia during Lent was developed at this time as well and it is very popular throughout Russia too.
The Immaculate Conception presents an interesting case example on its own. Kyivan Orthodox brotherhoods sprang up in honour of the Immaculate Conception (i.e. Confraternities) which took the "bloody vow" to defend to the death the Immaculate Conception of the Mother of God, they wore special medals of the Immaculate Conception (there are a few miraculous icons even in Russia of the Immaculate Virgin Mary which can be found on the Russian-language site: "pravicon.com" and there is also the practice of enshrining an RC statue of Our Lady of Loreto in some Orthodox monasteries and churches . . . in Russia).
Their Confraternity invocation was "All Immaculate Theotokos, save us!" And St Dmitri of Rostov belonged to such, as did other Orthodox saints and scholars (the ROC actually called St Dmitri to appear before the Synod on charges he had gone too far in this and some other devotions).
The Russian theologian Fr. Georges Florovsky commented on the Kyivan Mohyla academy in the 19th century and was non-plussed, shall we say, at the tremendous devotion of the entire academy to the ... Immaculate Conception!
And, of course, the May devotion with daily Molebens and Akathists is very strong in the UGCC today and also in certain Orthodox parishes.
Should the UGCC and other EC's divest themseles of any of this? I personally would say, "no" since they have withstood the test of time and have earned their right of liturgical citizenship.
As Fr. Isidore Dolnitsky once said, he prepared liturgical propers for these feasts to enable EC's to celebrate them in their own parishes, rather than attending RC parishes to do so.
Alex
Last edited by Orthodox Catholic; 06/11/15 08:58 AM.