captaincy vs headship

captaincy

noun
  • The rank or status of a captain. 

  • The jurisdiction of a captain. 

  • An administrative division of the former Spanish and Portuguese colonial empires. 

headship

noun
  • The position of a head or chief. 

  • The position of a headmaster or headmistress. 

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