armed struggle vs battle royal

armed struggle

noun
  • An irregular political conflict waged by an armed rebel group attempting to overthrow the prevailing regime or otherwise win political rights. 

battle royal

noun
  • A fight involving three or more individuals, teams, or factions; fought until one person, team, or faction is left standing. 

  • A heated discussion or debate. 

How often have the words armed struggle and battle royal occurred in a corpus of books? (source: Google Ngram Viewer )