Q. Why do we call liturgical chant “Gregorian”?
A. Christian liturgical chant has existed in various forms and languages since ancient times, with roots in the chant of the Jewish synagogue. Gregorian chant came to be the predominant form in the Western Catholic tradition. It’s a form of unison singing, unaccompanied and rhythmically free, used for centuries in the liturgy of the Catholic Church, both the Mass and the Divine Office.
Gregorian chant is named after Pope St. Gregory the Great (c. 540–604; feast day, September 3), during whose papacy (590–604) many of the existing forms of Western chant were collected and codified. The Frankish king Charlemagne (768–814) called for Gregorian chant to become the norm within his kingdom, where Gallican chant (another liturgical tradition) had been in common use. Then, in the eighth and ninth centuries, the Gregorian and Gallican chants became assimilated, and it’s the chant in this evolved form that has come down to the present.
Even though Gregorian remains the central tradition of Western chant, others are still employed in the Catholic Church: the Ambrosian (in Milan), the Mozarabic (a few locations in Spain), and the chants of the Eastern Rite Catholic Churches.