alighten vs set fire

alighten

verb
  • To make light; to illuminate or brighten. 

  • To lighten; to reduce in weight or heaviness. 

  • To alight, to dismount or get down from. 

  • To alight; to land, to descend and rest. 

set fire

verb
  • To light using fire; to cause to be on fire; to set alight. 

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