Caesar vs basileus

Caesar

noun

  • A title of Roman emperors. 

  • A Bloody Caesar cocktail. 

  • An absolute ruler; an autocrat. 

name

  • An ancient Roman family name, notably that of Julius Caesar. 

  • The government; society; earthly powers. 

basileus

noun

  • A title of the Byzantine emperor. 

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