Gregory is noted for having given us the Roman Canon, also called the
Mass of St. Gregory. It was a three-part formula of words that made up
the Mass as Jesus offered it at the Last Supper. In Our Lord's time, the
three-part grace at meals offered by all Jews, (and by Jesus) was left to the
individual hosts. They wanted it to express the host's sincere sentiment.
However, in 800, in Pope Gregory's time, the priests were not educated
enough to make up their own words. So, Pope Gregory put together the
words for the Mass that was much like the wording used by Jesus at the
Last Supper. It was the Latin Mass that I learned to offer aa a new priest.