Franciscan vs Grayfriar

Franciscan

noun
  • A monk or nun of related orders such as the Poor Clares. 

  • A member of the Order of the Friars Minor. 

adj
  • Of or related to the Franciscans. 

  • Of or related to St Francis of Assisi. 

Grayfriar

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