katabasis vs sanctum sanctorum

katabasis

noun
  • A retreat, especially a military one. 

  • A journey from the interior of a country to the coast. 

  • Any journey downwards or fall. 

  • The presence of downward (drainage or katabatic) winds. 

  • A mytheme or trope in which the hero embarks on a journey to the underworld. 

sanctum sanctorum

noun
  • A person's most private retreat or sanctuary. 

  • The Holy of Holies in the Jewish temple. 

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