bring to heel vs subdue

bring to heel

verb
  • To cause to act in a disciplined manner. 

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

subdue

verb
  • To overcome, quieten, or bring under control. 

  • To bring (a country) under control by force. 

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