republic vs sovereigndom

republic

noun
  • A state where sovereignty rests with the people or their representatives, rather than with a monarch or emperor; a country with no monarchy. 

  • One of the subdivisions constituting Russia. See oblast. 

sovereigndom

noun
  • The state, condition, or realm of a sovereign; sovereignty. 

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