Thank you, Vladimir. That was my impression. While it is true that most of Western Europe used Roman Latin-Rite Mass, there were medieval variants of it, even though the liturgical canon was settled by the 7th century (save maybe for inclusion of the Creed in the 11th).
But the same cannot be said of the earlier centuries, which were characterized by two aspects: lack of information about the Mass and canonical flux. I think it is safe to say that modern-day Catholics would recognize the Mass of the 7th century as their own.
Now, about the age of the TLM: Yes, the TLM was codified by Pius V. Its roots go much further back, with few substantial changes.
Yes, it seems that way.
From roughly the time of St. Gregory [d. 604] we have the text of the Mass, its order and arrangement, as a sacred tradition that no one has ventured to touch except in unimportant details.
Ciorrect.
The canon of the Mass dates back, in books that is, to at least the 4th or 5th century as we know from the great sacramentaries of Pope St. Leo (440-461), Pope Gelasius (492-496) and Pope St. Gregory the Great (590-604).
Yes, but the two centuries (5th and 6th) were the period when the Mass was undergoing most radical changes especially in canon. It was +Gregory I who basically settled the liturgical canon.
But I stand corrected: the TLM antiquity has bene in use since the 7th century (not quote 1,600 years but close!)
This existence of local development and variations between missals prior to their mass production by the printing press should not be source of scandal. I dear say that the situation in the Byzantine Rite at the time was similar. It should be remembered that the Great Entrance, that hallmark of the Byzantine liturgy, did not become current in Constantinople until the 6th/7th century. Even today there are differences in usages between the Greeks, Serbs, Russians, etc.