crown princess vs potentate

crown princess

noun
  • The heiress apparent to the throne in a royal or imperial monarchy. 

  • The wife of a crown prince. 

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 crown princess and potentate occurred in a corpus of books? (source: Google Ngram Viewer )