patron vs slave-driver

patron

noun
  • A padrone. 

  • A guardian or intercessor; synonym of patron saint. 

  • One who protects or supports; a defender or advocate. 

  • An influential, wealthy person who supported an artist, craftsman, a scholar or a noble. 

  • A customer, as of a certain store or restaurant. 

  • A protector of a dependent, especially a master who had freed a slave but still retained some paternal rights. 

  • One who has gift and disposition of a benefice. 

slave-driver

noun
  • An overseer of slaves at work; a person who puts slaves to work. 

  • An employer who demands excessive amounts of work from employees. 

How often have the words patron and slave-driver occurred in a corpus of books? (source: Google Ngram Viewer )