aevum vs spiritual world

aevum

noun
  • The temporal mode of existence between time and eternity, said to be experienced by angels, saints, and celestial bodies (which medieval astronomy believed to be unchanging. 

spiritual world

noun
  • A metaphysical plane of existence parallel to the material world and occupied by spirits and other unearthly forces. 

  • The afterlife. 

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