emirate vs principate

emirate

noun
  • A country ruled by an emir. 

  • The office of an emir. 

principate

noun
  • A state ruled by a prince; a principality. 

  • 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. 

adj
  • Primary; principal. 

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