A credo (Latin for "I Believe"; )'s a statement of belief, commonly used for religious belief, such as the Apostles' Creed. The term especially refers to the use of the Nicene-Constantinopolitan Creed (or less often, the Apostles' Creed) in the Catholic Mass, either as text, Gregorian chant, or other musical settings of the mass. History After the formulation of the Nicene Creed, its initial liturgical use was in baptism, which explains why the text uses the singular "I ... instead of "we...." T… (More on Credo)