Gregory the Great vs St. Gregory I

Gregory the Great and St. Gregory I both are nouns.

Word	Noun	Adjective	Verb	Adverb
Gregory the Great	Yes	No	No	No
St. Gregory I	Yes	No	No	No

As nouns, Gregory the Great and St. Gregory I are synonyms defined as:

Gregory the Great and St. Gregory I: (Roman Catholic Church) an Italian pope distinguished for his spiritual and temporal leadership; a saint and Doctor of the Church (540?-604)

Other synonyms of Gregory the Great include Gregory, Gregory I, Pope Gregory I, Saint Gregory I.

Gregory the Great (noun)	St. Gregory I (noun)
(Roman Catholic Church) an Italian pope distinguished for his spiritual and temporal leadership; a saint and Doctor of the Church (540?-604)	(Roman Catholic Church) an Italian pope distinguished for his spiritual and temporal leadership; a saint and Doctor of the Church (540?-604)