henceforward vs ultimately

henceforward

adv
  • from now on; from this time on 

ultimately

adv
  • Indicating the most important action. 

  • Indicating the last item. 

  • Used to indicate the etymon at which a given etymological derivation terminates. 

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