It is always a thrill to think of the centuries and millennia that have gone into making the venerable Liturgy we have today; how many saints, holy monks, nuns, priests and lay folk have sanctified themselves while celebrating or assisting at this Liturgy.
It is even more of a thrill when you can put your hands, so to speak, on evidence that much of that Liturgy is the same now as it was all those years ago.
This page of the manuscript Laon 239, written around the year 930, shows part of the Holy Mass for today, Septuagesima Sunday.
When comparing the text of that ancient Mass to the text used in today's celebration you can see that they are exactly the same.
Clearly the interpretation of the chant is a little different today (yes, those markings above the words are the neums of Gregorian Chant!), but the words of the Mass have remained unchanged for over 1000 years! Have a look at the Offertory, for example (highlighted in the manuscript):
Bonum est confiteri Domino et psallere nomini tuo Altissime.
It is good to give praise to the Lord: and to sing to thy name, O most High.