principality vs sovereignship

principality

noun
  • A region or sovereign nation headed by a prince or princess. 

  • A spiritual being, specifically in Christian angelology, the fifth level of angels, ranked above powers and below dominions. 

sovereignship

noun
  • The role or status of sovereign. 

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