That’s because these commemorations are POST-Nikonian!
The Greek Church had these commemorations before the Nikonian reforms, as did several Balkan and other Churches. Kyiv was always closer ecclesiastically to Constantinople for most of her history than Moscow.
While I am a fan of the Old Ritualists (and considered joining a community in my youth) as a Greek Catholic I do not refuse all post-Nikonian developments. Many newer saints, men of holiness and spiritual leadership, martyrs, etc. will unfortunately never be commemorated amongst the Old Ritualists.
As you say, the pre-Nikonian service books of the early 17th century have St. Gregory’s commemoration on his day of repose itself in November, and not the translation to the 2nd Sunday of the Great Fast.
This was done in the Muscovite church after the Nikonian reforms to conform with the Greek practice of the second Sunday of the Great Fast, which was instituted as I recall about a century after St. Gregory’s glorification (or about in the late 15th century). The Kyivan Church, closer to Constantinople, may have done this even sooner.
FWIW, I one etime had a small Chasoslov published by Met. Andrew Sheptitsky, and these commemorations were not in there, either.
Even some older Orthodox chasoslovia did not include this commemoration, either, probably because of the small size of the volume and the fact that this was a one-day-a year commemoration.
Regarding this specific volume you refer to, the
Ordo and
Anthologia as well as the other liturgical books were all printed years after this volume (which as I recall was also printed by the Basilians, which may greatlly explain its ommission).
The restoration of our liturgical and spiritual heritage should not be static. The
Instruction from Rome exhorts us to minimize differences in liturgical practice with the Orthodox; in keeping with the letter and intent of the
Instruction all of the non-Muscovite Churches of the Kyivan tradition that are sister Churches to the UGCC keep St. Gregory’s commemoration on the second Sunday of the Great Fast.
Since Rome has also blessed St. Gregory’s liturgical restoration in official liturgical books published by the Holy See, and our hierarchs themselves have recommended this restoration (Patriarch Josyp and more recently Bishop +Basil Losten in the
Paschal Pilgrimage) , and it is perfectly consistent with the
Instruction from Rome, the path is clear regarding St. Gregory’s commemoration on the Second Sunday of the Great Fast.
