Pepin the Short vs Pepin III

Pepin the Short and Pepin III both are nouns.

Word	Noun	Adjective	Verb	Adverb
Pepin the Short	Yes	No	No	No
Pepin III	Yes	No	No	No

As nouns, Pepin the Short and Pepin III are synonyms defined as:

Pepin the Short and Pepin III: king of the Franks and father of Charlemagne who defended papal interests and founded the Carolingian dynasty in 751 (714-768)

Other synonyms of Pepin the Short include Pepin.

Pepin the Short (noun)	Pepin III (noun)
king of the Franks and father of Charlemagne who defended papal interests and founded the Carolingian dynasty in 751 (714-768)	king of the Franks and father of Charlemagne who defended papal interests and founded the Carolingian dynasty in 751 (714-768)