ne plus ultra vs nonesuch

ne plus ultra

noun
  • The perfect or most extreme example of its kind; the ultimate. 

  • A prohibition against proceeding further; an insuperable obstacle or limiting condition. 

  • The highest, ultimate point of achievement which can be reached; perfection. 

nonesuch

noun
  • A person or thing with no equal. 

  • Silene chalcedonica (syn. Lychnis chalcedonica) 

How often have the words ne plus ultra and nonesuch occurred in a corpus of books? (source: Google Ngram Viewer )