city manager vs seneschal

city manager

noun
  • A municipal official responsible for the operations of a city, usually appointed by a town or city council rather than elected. 

seneschal

noun
  • A steward, particularly (historical) one in charge of a medieval nobleman's estate. 

  • An officer of the crown in late medieval and early modern France who served as a kind of governor and chief justice of the royal court in Normandy and Languedoc. 

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