enslave vs ransom

enslave

verb
  • To make subservient; to strip one of freedom; enthrall. 

ransom

verb
  • To exact a ransom (payment) in exchange for the freedom of. 

  • To pay a price to set someone free from captivity or punishment. 

noun
  • The release of a captive, or of captured property, by payment of a consideration. 

  • A sum paid for the pardon of some great offence and the discharge of the offender; also, a fine paid in lieu of corporal punishment. 

  • Money paid for the freeing of a hostage. 

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