herald vs make known

herald

verb
  • To proclaim or announce an event. 

  • To greet something with excitement; to hail. 

noun
  • A harbinger, giving signs of things to come. 

  • A handbill consisting of an advertisement. 

  • An official whose speciality is heraldry, especially one between the ranks of pursuivant and king-of-arms. 

  • A messenger, especially one bringing important news. 

  • A moth of the species Scoliopteryx libatrix. 

make known

verb
  • To announce (some information) generally. 

  • To disclose (a secret). 

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