Gregorian chant
Gregorian chant, and its close cousin, Old Roman chant, were a repertory of ritual melodies, possibly influenced by the equivalent music in the Jewish liturgy, in the first few centuries of the Christian church. Much of it survives in manuscripts of the 11th to 13th centuries. Whilst originally thought to be the style of chant used in Rome during Gregoryâs ministry (590-604 A.D.) it is now believed to have originated in the Frankish Empire during Charlemagneâs reign when Roman liturgy was introduced there.
It began to be replaced by polyphony as a musical style in services during the High Middle Ages.