Roger de Mortimer vs Roger Mortimer

Roger de Mortimer and Roger Mortimer both are nouns.

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

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

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

Other synonyms of Roger de Mortimer include Mortimer.

Roger de Mortimer (noun)	Roger 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)