Gregory XIII vs Ugo Buoncompagni

Gregory XIII and Ugo Buoncompagni both are nouns.

Word	Noun	Adjective	Verb	Adverb
Gregory XIII	Yes	No	No	No
Ugo Buoncompagni	Yes	No	No	No

As nouns, Gregory XIII and Ugo Buoncompagni are synonyms defined as:

Gregory XIII and Ugo Buoncompagni: the pope who sponsored the introduction of the modern calendar (1572-1585)

Other synonyms of Gregory XIII include Gregory, Pope Gregory XIII.

Gregory XIII (noun)	Ugo Buoncompagni (noun)
the pope who sponsored the introduction of the modern calendar (1572-1585)	the pope who sponsored the introduction of the modern calendar (1572-1585)