hierarch vs primate

hierarch

noun
  • A title of bishops in their role as ordinaries (arbiters of canon law) over their respective dioceses. 

  • One who has high and controlling authority in sacred things; the chief of a sacred order. 

primate

noun
  • In the Catholic Church, a rare title conferred to or claimed by the sees of certain archbishops, or the highest-ranking bishop of a present or historical, usually political circumscription. 

  • In the Anglican Church, an archbishop, or the highest-ranking bishop of an ecclesiastic province. 

  • A mammal of the order Primates, including simians and prosimians. 

  • A simian anthropoid; an ape, human or monkey. 

  • In the Orthodox Church, the presiding bishop of an ecclesiastical jurisdiction or region. Usually, the expression primate refers to the first hierarch of an autocephalous or autonomous Orthodox church. Less often, it is used to refer to the ruling bishop of an archdiocese or diocese. 

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