sachem vs warlord

sachem

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

  • A boss, a leader. 

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

warlord

noun
  • A high military officer in a warlike nation. 

  • A local ruler or bandit leader usually where the government is weak. 

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