bilboes vs persecution

bilboes

noun
  • An iron bar fitting around the ankles of prisoners, and having sliding shackles. 

persecution

noun
  • The act of persecuting. 

  • A program or campaign to subjugate or eliminate a specific group of people, often based on race, religion, sexuality, or social beliefs. 

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