Vicar of Christ vs Pius VI

Vicar of Christ and Pius VI both are nouns.

Word	Noun	Adjective	Verb	Adverb
Vicar of Christ	Yes	No	No	No
Pius VI	Yes	No	No	No

Vicar of Christ (noun)	Pius VI (noun)
the head of the Roman Catholic Church	Italian pope from 1775 to 1799 who served during the French Revolution; Napoleon attacked the Papal States and in 1797 Pius VI was taken to France where he died (1717-1799)