Why Do Catholics Pray the Creed? by Life Teen • October 3, 2012 The YouCat describes a creed as a 'bried formula of faith that makes it possible for all believers to make a common profession' (YouCat 26). The two most used creeds of the Catholic Church are the Nicene Creed and the Apostle’s Creed. In Mass, we pray the Nicene Creed, which was written during two of the great councils of the Church, Nicacea in 325 A.D. and Constantinople in 381 A.D. It's the Church's way of briefly summarizing the most important truths of the faith.