Keeper vs Marshal

Keeper

name
  • An English surname originating as an occupation for the keeper of a castle. 

Marshal

name
  • An English and Scottish status surname from Middle English for someone who was in charge of the horses of a royal household, or an occupational surname for someone who looked after horses, or was responsible for the custody of prisoners. 

  • A male given name transferred from the surname, of 19th century and later usage. 

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