overlordship vs superiority

overlordship

noun
  • The position or quality of being an overlord. 

  • The realm of overlords. 

superiority

noun
  • The state of being superior. 

  • The right which the superior enjoys in the land held by the vassal. 

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