mettle vs valiance

mettle

noun
  • A quality of endurance and courage. 

  • Good temperament and character. 

adj
  • Spirited, vigorous, stout-hearted. 

valiance

noun
  • The quality of being valiant; heroism, bravery or valour. 

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