fealty vs treason

fealty

noun
  • Fidelity to one's lord or master; the feudal obligation by which the tenant or vassal was bound to be faithful to his lord. 

  • The oath by which this obligation was assumed. 

treason

noun
  • An act of treachery, betrayal of trust or confidence. 

  • The crime of betraying one’s own country. 

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