swain vs valentine

swain

noun
  • A rural lover; a male sweetheart in a pastoral setting. 

valentine

noun
  • A person to whom a valentine is given or from whom it is received, especially on February 14th. 

  • An expression of affection, especially romantic affection, usually in the form of greeting card, gift, or message given the object of one's affection, especially on February 14th. 

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