Pied Piper vs Pied Piper of Hamelin

Pied Piper and Pied Piper of Hamelin both are nouns.

Word	Noun	Adjective	Verb	Adverb
Pied Piper	Yes	No	No	No
Pied Piper of Hamelin	Yes	No	No	No

As nouns, Pied Piper and Pied Piper of Hamelin are synonyms defined as:

Pied Piper and Pied Piper of Hamelin: the title character in a German folk tale and in a poem by Robert Browning

Pied Piper (noun)	Pied Piper of Hamelin (noun)
the title character in a German folk tale and in a poem by Robert Browning	the title character in a German folk tale and in a poem by Robert Browning