In the early Middle Ages, the European church used several different religious ritual songs. Byzantine chants combined elements of ancient Greek and Eastern music and adopted a classification method of eight modes. The Ambrosian Psalm is a hymn compiled by St. Ambrose of Milan (St. Ambrose, Bishop of Milan from 374 to 397). He introduced Syrian antiphonal hymns to Western Europe for the first time and compiled a popular Hymns. In addition, there are Frankish Gallic chants and Spanish Mosalab chants.

It is said that at the end of the 6th century AD, Pope Gregory I (reigned from 590 to 604), in order to unify church rituals, collected and selected ritual songs, hymns, etc. used by various churches into " A collection of hymns, called Gregorian Psalms.

There are two existing early Gregorian chants. One is the Frankish-style chant that was spread in the Frankish Kingdom in the 8th to 9th centuries AD. This is a copy handed down by King Charlemagne of the Franks who vigorously promoted the standard Roman Mass rituals and chants in the vast area he ruled; the other is an ancient Roman copy from the 11th to 13th centuries AD. According to research, its history Dating back to the 8th century AD.

Gregorian chant is monophonic music, with Latin words, sung by a male voice, and the score is only a record of pitch but no beat. Gregorian chant is mainly used in the daily prayer classes and mass rituals of the Catholic Church. It has strong religious concepts and functions, pursuing a spirit of "the other side" that is transcendent from this world, and avoiding worldly personal emotions.

Some of the words of Gregorian Psalm are taken from the Bible, some are in prose, and some are in poetry. Singing methods include: antiphonal (two groups of choruses alternate), response (responsorial (lead and chorus respond)) and solo or chorus singing. It has three main types of melody: syllabic, in which one Latin syllable of the lyrics is paired with one sound; cantata, in which one syllable of the words is paired with a drawl; chanting, in between the first two, with one syllable sung from 2 to 4 or 5 tones. There are eight types of modes in Gregorian chant: four regular modes, Dorian, Phrygian, Lydian and Mixed Lydian, as well as four deflections derived from them.