first minister vs sachem

first minister

noun
  • The principal minister of a ruler or state. 

  • A leader of a devolved government such as Scotland, Wales, or Northern Ireland. 

  • The prime minister or a provincial or territorial premier. 

sachem

noun
  • A boss, a leader. 

  • A chief of one or several Native American tribe(s), especially of the Algonquians; a sagamore. 

  • A high-ranking officer of the Tammany Hall political organization. 

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