Marshal vs Raven

Marshal

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

  • 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. 

Raven

name
  • A male given name 

  • A surname. 

  • A female given name from English for a girl with raven hair, used since the 1970s. 

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