principate vs sovereignty

principate

noun
  • The office of one who is principal or preeminent (such as a prince); the quality or status of being principal; preeminence. 

  • The early period of the Roman Empire, during which some characteristics of the government of the Roman Republic were retained; the reign of any particular emperor during said period. 

  • A state ruled by a prince; a principality. 

adj
  • Primary; principal. 

sovereignty

noun
  • Of a ruler: supreme authority over all things. 

  • An independent or sovereign territory. 

  • Of a polity: the state of making laws and controlling resources without the coercion of other nations. 

  • Of a person: the liberty to decide one's thoughts and actions. 

  • Excellence, mastery, preeminent efficacy. 

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