fess vs make known

fess

verb
  • To confess; to admit. 

adj
  • Of animals, bad-tempered, fierce. 

  • Lively; active; strong. 

  • Proud; conceited. 

noun
  • A horizontal band across the middle of the shield. 

make known

verb
  • To disclose (a secret). 

  • To announce (some information) generally. 

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