credo vs theology

credo

noun
  • A statement of a belief or a summary statement of a whole belief system; also (metonymically) the belief or belief system itself. 

  • The liturgical creed (usually the Nicene Creed), or a musical arrangement of it for use in church services. 

theology

noun
  • A particular belief within a religion. 

  • Synonym of religious studies 

  • Subjective marginal details. 

  • An organized method of interpreting spiritual works and beliefs into practical form. 

  • The study of God, a god, or gods; and of the truthfulness of religion in general. 

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