caesar vs oligarch

caesar

noun
  • emperor, ruler, dictator 

  • Any agaric mushroom of the genus Amanita, section Amanita sect. Caesareae. 

oligarch

noun
  • A member of an oligarchy; someone who is part of a small group that runs a country. 

  • A very wealthy business owner who wields political power. 

  • A protoplanet formed during oligarchic accretion. 

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