ataraxy vs serenity

ataraxy

noun
  • State of psychological calm and tranquility, absence of discomfort, or metabolical inactivity. 

  • Ataraxia; freedom from mental disturbance; imperturbability, dogged indifference. 

serenity

noun
  • The state of being serene; calmness; peacefulness. 

  • A lack of agitation or disturbance. 

  • A title given to a reigning prince or similar dignitary. 

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