early morning vs terce

early morning

noun
  • the time between midnight and sunrise 

terce

noun
  • The third hour of daylight (about 9 am). 

  • The service appointed for this hour. 

  • A widow's right, where she has no conventional provision, to a liferent of a third of the husband's heritable property. 

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