SEE NOW comment on the thread by Hierodeacon.
According to Corriere della Sera, the Pope has again made the suggestion, which the British Press widely reported him as making more than a year ago in May 2014 when he met His All-Holiness the Patriarch Bartholomew, of a common date for Easter among all Christians. What reporters seem to be uncertain about is whether (1) he is suggesting to Orthodox Patriarchs the proposal discussed half a century ago at Vatican II, of fixing a particular Sunday to which we should all move, with both East and West abandoning their respective Julian and Gregorian Easters; or whether (2) he is going for the distinctly easier option of simply bringing the Latin Churches into line with the Julian Calendar ("adopting the Orthodox Easter"). He feels that it is embarrassing for Christians to say to each other "So when was your Jesus resurrected?"
Frankly, it would be easiest for the West to adopt (2) the Julian (Eastern) calculations. This is because it would be immensely difficult to persuade the Orthodox to change at all. The Orthodox have hitherto never been able to agree even amongst themselves about such changes (attempts in Orthodoxy to make alterations to Calendars have been known to lead to schisms termed 'Old Calendarist'). An obvious example: the Orthodox Autocephalous Churches, although united in celebrating Easter and the other moveable feasts on the Julian dates, have never been able to agree amongst themselves about the celebration of the fixed festivals, such as Christmas/December 25. So the Greek Church (but not the Holy Mountain) is 'Gregorian' and keeps Christmas on the same day as we do in Latin Christendom; but for the Russian Church and some other Slavs who are 'Julian', "December 25" does not arrive until the day we call January 7. Put an Orthodox Greek and an Orthodox Russian into the same room and they might easily start fighting about "So when was your Jesus born?". Unless the Greek belongs to one of the three Old Calendarist sects! Or is a monk from Athos!
For the West to adopt, under the guidance of the Sovereign Pontiff, (2), the Julian ("Orthodox") Easter, would have the highly, the exquisitely amusing result of shifting the Latin Churches back to how things were when S Pius V promulgated his Missal and Breviary (until 1582, of course, all the world kept the Julian - "Orthodox" - Easter). Pope Francis would suddenly appear in the role of the man who moved the West back to the Tridentine dates! "All together now, back to S Pius V!" "Quo primum rules OK!" I bet neither his friends nor his foes have hitherto seen Francis in this ultra-traddy light! I rather like it!! His Excellency Bishop Fellay must be breaking open the champagne, if they have any in the cellars at Econe ... do you think they do? Pol Roger, perhaps? I once met a man who ... Oh dear, encroaching senility makes it so difficult for me to stick to the point ... these temptations to take trips down Memory Lane ...
But Western governments ... not to mention the tourist and 'leisure' trades ... are unlikely to view with much enthusiasm (2) the adoption of a Julian Easter which can sometimes be as much as six weeks later than our present Western Gregorian Easter. What secular interests have, since the 1920s, always wanted is (1) an Easter fixed on ... for example ... the second Sunday of April. If Pope Francis hopes to persuade all the separate Autocephalous Byzantine Churches, not to mention the non-Chalcedonian communions who now like to be known as 'Oriental Orthodox', to dump the Nicene calculations which they have insisted on sticking to for seventeen hundred years, and to agree to (1) a comfortable 'secular' date like the Second Sunday in April, I hope he's confident that he's going to be living for an enormously long time!
FOOTNOTE In fact, the rule of the Catholic Church at the moment is that, in countries (such as Greece) where the dominant Christian community observes the Julian ("Orthodox") Easter, even the Latin Rite Christians should do the same so that there will indeed only be one Easter. Orthodox Eastern communities domiciled in traditionally Catholic or Protestant lands are not, of course, prepared to make a symmetrical concession because "it would go against Nicea".
FOOTNOTE The December 25/January 7 business has nothing to do with the Theophany/Epiphany. And the Easter difficulty is in no way connected with the problems (related in S Bede) about 'Celtic' calculations of Easter. Or with the Quartodecimans. Comments which muddy the waters by implying that there are some connections here will not be accepted. Our present divergence only arose in 1582, when the West broke ranks with the East by changing to the Gregorian Calendar. We did so ... what pedants we Latins are ... on the specious grounds that the real, astronomical, Solstices and Equinoxes and the movements of the Sun through the zodiacal zones were no longer happening on the days on which the ecclesiastical calendars claimed they were! Nor will I accept comments which condescendingly inform me of something I've already said ... yes, people do that! Why bother, they feel, to read the whole article before putting the old gentleman right!