madrigal vs tenson

madrigal

noun
  • A polyphonic song for about six voices, from 16th century Italy. 

  • A song for a small number of unaccompanied voices; from 13th century Italy. 

  • A short poem, often pastoral, and suitable to be set to music. 

tenson

noun
  • A form of lyric poem used by troubadours in Provençal in which two voices present different sides of an argument, in alternate stanzas, lines, or groups of lines with identical structure. 

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