potentate vs seigneur

potentate

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

  • A self-important person. 

  • A powerful polity or institution. 

  • Someone acting in an important role. 

seigneur

noun
  • A feudal lord or noble in French contexts. 

  • The hereditary feudal ruler of Sark. 

  • A landowner in Canada; the holder of a seigneurie. 

  • A hereditary title in the Bailiwick of Jersey. 

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