principality vs world power

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. 

world power

noun
  • A nation or state so powerful that it can influence world affairs. 

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