bygone vs past historic tense

bygone

noun
  • An event that happened in the past. 

adj
  • Having been or happened in the distant past. 

past historic tense

noun
  • A tense used in some languages (such as French and Italian) in narrative, and in spoken language primarily when reading narrative or in storytelling, for completed actions in the past or in speaking of the dead. It is semantically the same as the simple past in many languages, including English. 

How often have the words bygone and past historic tense occurred in a corpus of books? (source: Google Ngram Viewer )