protectorate vs rulership

protectorate

noun
  • The authority assumed by a superior power over an inferior or a dependent one, whereby the former protects the latter from invasion and shares in the management of its affairs but the protected state retains its nominal sovereignty. 

  • An autonomous territory that is protected diplomatically or militarily against third parties by a stronger state or entity. 

  • Government by a protector; especially, the government of England, Scotland, and Ireland by Oliver Cromwell. 

rulership

noun
  • A position in which one rules or has sovereignty over others. 

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