heirship vs legacy

heirship

noun
  • The status of being heir to something or someone 

legacy

noun
  • Something inherited from a predecessor or the past. 

  • The descendant of an alumnus. 

  • Money or property bequeathed to someone in a will. 

adj
  • Left over from the past; no longer current. 

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