grand dukedom vs seigneur

grand dukedom

noun
  • The title of grand duke or grand duchess, with its pertaining privileges and obligations; contrast grand duchy. 

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 grand dukedom and seigneur occurred in a corpus of books? (source: Google Ngram Viewer )