bethink vs retrospect

bethink

verb
  • To think of (something or somebody) or that (followed by clause); to remind oneself, to consider, to reflect upon. 

  • To meditate, ponder; to consider. 

  • To determine, resolve. 

retrospect

verb
  • To look or refer back to; to reflect on. 

noun
  • Consideration of past times. 

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