Credo
Profession of faith; third chant of the Mass Ordinary.
What it means
The Credo (Latin for "I believe") is the third of the five chants of the Mass Ordinary, the parts of the Mass whose text does not change with the liturgical calendar. It sets the Nicene-Constantinopolitan Creed of the Christian church, making it the theologically densest and textually longest movement of any Ordinary setting.
In the order of the Mass, the Credo comes after the Gospel and before the eucharistic section with the Sanctus and Agnus Dei. Unlike the Kyrie, Gloria, Sanctus, and Agnus Dei, it was not originally a liturgical chant of the Mass but was only incorporated in the early Middle Ages.
Musical use
Because of its long, irregularly structured text, the Credo poses particular challenges for composers: many multi-movement Mass settings divide it into several contrasting sections, often to highlight the central moments "et incarnatus est", "crucifixus", and "et resurrexit". Well-known examples occur in the great Mass settings of Johann Sebastian Bach (Mass in B minor), Wolfgang Amadeus Mozart, and Ludwig van Beethoven.
The "Crucifixus" section is often set with particular gravity, frequently in minor with chromatic harmony, while "Et resurrexit" typically follows as a jubilant contrast in brighter keys and a faster tempo.