AJV,
just to make sure we are on the same page…i’m not including the changes after V2. i’m referring of the changes up to the 1962 missal.
there were changes to the order of holy week in 1955, if i’m not mistaken. that was pretty major.
i think most traditional catholics would agree that a priest in the decades immediately preceding Pp St Gregory could walk into a MAss offerred according to the 1962 missal and feel at home. were he to walk into a typical NO mass, he would not.
I’m not really sure about the last statement: though I agree that the Mass did organically evolve.
At the time of St. Gregory:
Everything unto the Introit was not there
The Kyrie could be replaced by a litany
the Gloria was not in use as extensively as now: mostly reserved for bishops
The Creed was also not said
There were no Offertory prayers at all except for the Secret. It was not preceded by Orate Fratres
The Canon was mostly like it is in the TLM except that the certain parts were not said on Sundays.
The Lord’s Prayer and embolism is mostly like it is in the TLM
The Angus Dei may have been repeated more times.
There were no private prayers for the priest’s communion and no ablution prayers (though one of those in the TLM “Quod Ore” is ancient but was used for something else)
Postcommunion followed by Ite Missa est. The blessing, as is evident from its position, was only introduced later especially for priests.
No Last Gospel
Besides the whole ceremonial was different. As requested by TNT, I will try and post the instructions given for that time, and I think then it will be more evident. I think except for the Canon (barring all the ceremonies) a priest of St. Gregory would find it quite different.
If one went from before St. Gregory there would be changes in the Kyrie, the position of the Our Father, and depending how early (like back to Pope Innocent), even in the Canon and the Offertory (because some say that at that time, based on his letter to the bishop of Gubbio, the commemoration for living and the dead was made at the Offertory) .