magus vs theurge

magus

noun
  • A magician; (derogatory) a conjurer or sorcerer, especially one who is a charlatan or trickster. 

  • A Zoroastrian priest. 

theurge

noun
  • One who works miracles, or persuades a god or spirit to perform a supernatural work. 

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