Duke of Wellington vs national leader

Duke of Wellington and national leader both are nouns.

Word	Noun	Adjective	Verb	Adverb
Duke of Wellington	Yes	No	No	No
national leader	Yes	No	No	No

Duke of Wellington (noun)	national leader (noun)
British general and statesman; he defeated Napoleon at Waterloo; subsequently served as Prime Minister (1769-1852)	a person who is a respected leader in national or international affairs