grand duke vs pharaoh

grand duke

noun
  • Ruler or monarch of a grand duchy. 

  • Son or grandson of a czar (emperor) of the Russian Empire. (A more literal translation of the Russian would be grand prince.) 

pharaoh

noun
  • The supreme ruler of Ancient Egypt; a formal address for the sovereign seat of power as personified by the "king" in an institutional role of Horus son of Osiris; often used by metonymy for Ancient Egyptian sovereignty 

  • The card game faro. 

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