grand vizier vs gubernator

grand vizier

noun
  • A figure of great authority and power. 

  • The greatest minister of a sultan, with absolute power of attorney and, in principle, dismissable only by the sultan himself. 

gubernator

noun
  • Leader. 

  • Governor. 

How often have the words grand vizier and gubernator occurred in a corpus of books? (source: Google Ngram Viewer )