pharaoh vs potentate

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. 

potentate

noun
  • A powerful leader; a monarch; a ruler. 

  • A self-important person. 

  • A powerful polity or institution. 

  • Someone acting in an important role. 

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