bring to heel vs subjugate

bring to heel

verb
  • To compel someone to obey; to force someone into a submissive condition. 

  • To cause to act in a disciplined manner. 

subjugate

verb
  • To forcibly impose obedience or servitude upon. 

adj
  • In a subjugated position. 

How often have the words bring to heel and subjugate occurred in a corpus of books? (source: Google Ngram Viewer )