affirm vs attorn

affirm

verb
  • To make firm; to confirm, or ratify; especially (law) to assert or confirm, as a judgment, decree, or order, brought before an appellate court for review. 

  • To agree, verify or concur; to answer positively. 

  • To state under a solemn promise to tell the truth which is considered legally equivalent to an oath, especially of those who have religious or other moral objections to swearing oaths; also solemnly affirm. 

  • To assert positively; to tell with confidence; to aver; to maintain as true. 

  • To support or encourage. 

attorn

verb
  • To acknowledge the jurisdiction of (a particular court) over one's dispute. 

  • To consent to the transfer of one's obligations as tenant under a lease to a new landlord. 

  • To transfer one's obligations from a person to another person. 

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