The Patriarch of Constantinople believes that only historical differences rather than dogmas separate Orthodoxy and Catholicism, hence their unity is

[OrbisNonSufficit]

When was the last time Rome united with the Armenian Orthodox church?

Not sure if that was what it was, but even after Union of Florence failed, numerous Armenians converted to Catholicism, which in effect created Armenian Catholic Church… Armenia was united with Catholic Church some time after 6th Ecumenical Council, then during Crusades and then during Council of Florence… later attempts actually only managed to result into Armenian Catholic Church.

 

[dvdjs]

That is , because there was a period where the Patriarch of Constantinople was in communion with Rome, from the July 6, 1439 union.

The Metropolitan of Kiev Isdiadore led the union effort at Florence. Several successors of him remained united with Rome.

• Gregory II, 1458–1473 – Catholic metropolitan appointed by Pope Pius II
• Misail Pstruch, 1476–1480 [25] – Catholic metropolitan accepted by Casimir IV Jagiellon, king of Poland and grand duke of Lithuania, after agreeing to adopt the 1439 Union of Florence; appointed by Pope Sixtus IV
• Spyridon Satana [ru; uk], 1476–1482 [26] – consecrated as Orthodox metropolitan of Kiev by Patriarch Raphael I of Constantinople but rejected by Casimir IV
• Symeon, metropolitan of Kyiv [ru; uk], 1481–1488 [26] – first accepted Orthodox metropolitan since 1458

 

[HesyCath]

My guess is that Patriarch Kirill will name himself the Ecumenical Patriarch and declare the Greeks to be in schism.

First of all, the Moscow Patriarchate has already declared the Ecumenical Patriarchate to be schismatic; due to the whole Ukrainian Autochephaly fallout.

The Patriarch of Moscow probably wouldn’t declare himself "primus inter pares because the Patriarch of Antioch would be the highest in honor canonically (since Constantinople and Alexandria had become schismatic).

 

[HesyCath]

I heard that in 1968 there was a meeting between the Oriental Orthodox and the Eastern Orthodox and that there was and understanding and that the Christological differences were resolved.

They produced a document that was full of nonsense and platitudinal remarks, but it has proved to be empty words, and the Monophysites continue obstinately in their heresy.

 

[HesyCath]

Yes . . . but I would generally expect the core of that (outsider of the ROC) to be some of the Mt. Athos monasteries.

This is sort of true. Among the more liberal monasteries, such as Xenophontos or Pantocrator, Ukrainian Autocephaly is strongly promoted. In fact, a monk from Xenophontos actually wrote the Tomos of Autocephaly given to Philaret Denisenko.

The Slavic monasteries on Mt. Athos are very opposed to Ukrainian Autocephaly, especially St. Panteleimon (the Russian monastery). I have heard that many monks at St. Panteleimon will actually wear the St. George ribbon. Among the more traditional Greek monasteries (Great Lavra, Simonos Petras, Philotheou, and the sketes and cells) Ukrainian autocephaly is also frowned upon.