at one time vs heretofore

at one time

prep
  • formerly 

  • simultaneously, at once. 

heretofore

adv
  • Previously within the present text; earlier herein. 

  • Before now, until now, up to the present time; from the beginning to this point. 

How often have the words at one time and heretofore occurred in a corpus of books? (source: Google Ngram Viewer )