piece of art vs vertu

piece of art

noun
  • Synonym of work of art 

vertu

noun
  • Objets d'art collectively. 

  • Especially with reference to the writings of Machiavelli (1469–1527): the requisite qualities for political or military success; vitality, determination; power. 

  • The fine arts as a subject of study or expertise; understanding of arts and antiquities. 

  • Moral worth; virtue, virtuousness. 

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