sunder vs unify

sunder

verb
  • To break or separate or to break apart, especially with force. 

  • To part, separate. 

noun
  • a separation into parts; a division or severance 

unify

verb
  • Cause to become one; make into a unit; consolidate; merge; combine. 

  • Become one. 

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