Roger de Mortimer vs Mortimer

Roger de Mortimer and Mortimer both are nouns.

Word	Noun	Adjective	Verb	Adverb
Roger de Mortimer	Yes	No	No	No
Mortimer	Yes	No	No	No

As nouns, Roger de Mortimer and Mortimer are synonyms defined as:

Roger de Mortimer and Mortimer: English nobleman who deposed Edward II and was executed by Edward III (1287-1330)

Other synonyms of Roger de Mortimer include Roger Mortimer.

Roger de Mortimer (noun)	Mortimer (noun)
English nobleman who deposed Edward II and was executed by Edward III (1287-1330)	English nobleman who deposed Edward II and was executed by Edward III (1287-1330)