The designation is rather that of empire. When Constantine moved the seat of Empire to Constantinople to make a distinctively Christian capital without memories of the pagan imperial past, that was the Second Rome, or "New Rome."
When Constantinople and the last vestige of the Christian Roman Empire fell in the 15th century, this coincided with the rise of Russia as a large, Orthodox Christian nation. Russia did see itself as a successor to the Orthodox Roman Empire, and throughout most of its history, took its role very seriously in looking out for the interests of Orthodoxy around the world. There is a sense in which that attitude is being reborn in Russia today.
I am unaware of *anything* that indicates that the "Third Rome" moniker was the result of believing that Constantinople had fallen into heresy. I'm not sure where you would get that.
In fact, in the 16th century, after the fall of Constantinople, when Patriarch Nikon came to an awareness that there was a divergence of Russian service books from those in use in the Greek world, he immediately undertook a reform of the Slavonic service books to bring them into conformity with those in use in Constantinople, assuming that they were correct and the Slavonic books were wrong. In some cases he was right to assume this, and in other cases, it was actually the Slavonic readings that were older, but the point is that he deferred to the Greek world. These reforms caused the Old Believer schism, which hurt the Russian church deeply, and there were other negative aspects to it, including the loss of much of the living ancient Znamenny chant tradition, that is only now being recovered. These are not the actions of a Russian church which believes that Constantinople was in heresy.
I would also be careful with interpreting "excommunication" through Roman eyes. When the Pope excommunicates someone, then he's out of the Church. When one Orthodox primate "excommunicates" another primate, what is usually being spoken of is a "breaking of communion." In the Orthodox world, communion can be broken without a declaration that someone is outside the Church.
You are of course right that the Orthodox liturgy has developed (mostly by things being added) over time. No Orthodox Christian with a knowledge of the Liturgy would ever question that. But the changes and development have been quite gradual and organic. There have never been the kinds of sea-changes that happened in the Western liturgy after Vatican II. Pope Benedict has written on this.
One thing that is certain, though -- any Christian from the 5th century, East or West, could land in my parish on a Sunday morning and would know what was going on. I can pretty much guarantee that the same wouldn't be true if he were to land in one of our local Catholic parishes.
Your implied criticism of the liturgical reform mandated by Vatican II is accurate. The current Roman Rite of the mass bears little resemblance to the glorious liturgy that was celebrated for nearly 1500 years in the west. The horrible bungling of the reform of the liturgy is another reason to bemoan the "romanization" of the Christian west. The preservation of other ancient and unimpeachably orthodox (lower case "o") liturgical rites would have served as a safeguard against the introduction of the liturgical concoction that has been foisted upon us. The gradual elimination of most of the other ancient rites in the west after Trent is something else that this Pope has expressed regret over. One can never be sure but there is hope among orthodox Catholics that one of the items high on Benedict's agenda is fixing the liturgical mess.
I just want to respond briefly to a couple of points:
I am unaware of *anything* that indicates that the "Third Rome" moniker was the result of believing that Constantinople had fallen into heresy. I'm not sure where you would get that.
I think you're right, I think I misquoted the original ditty, which I think went, "The first Rome fell into heresy, the second Rome fell to the Turks, Two Romes have fallen. The third stands. And there will not be a fourth. No one will replace your Christian Tsardom!" The monk Filofei saod this in a panegyric to Tsar Vasili III in 1510. I stand corrected, my mistake.
You can read the whole thing here: http://college.hmco.com/history/west/mosaic/chapter8/source301.html
...There have never been the kinds of sea-changes that happened in the Western liturgy after Vatican II. Pope Benedict has written on this.
One thing that is certain, though -- any Christian from the 5th century, East or West, could land in my parish on a Sunday morning and would know what was going on. I can pretty much guarantee that the same wouldn't be true if he were to land in one of our local Catholic parishes.
I think that Christians of any age would recognize the sequence of the Mass, the Liturgy of the Word and of the Eucharist, the place of the Creed, of the epiclesis and the anaphora. I don' see this structure having changed at all. The rubrics, the readings, sure, they have changed.
But so what? There are things that can be said abou not changing. Where would that leave us? It leaves us arguing about who is first in the Kingdom of Heaven, which is where the matter has stood for 1,000 years.
-Theo
You saw almost the same thing happen to the Japanese Nagasaki Catholics (Kakure Kirishitan, or hidden Christians) who lived without contact with the West or without clergy for 200 years. Their Christianity was in error and they got many facts wrong as one can expect to happen when you lose contact with the outside world and are forced to hide the fact you are a Christian.