alighten vs shed light on

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. 

shed light on

verb
  • To illuminate; to make clear. 

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