The liturgical form of song known as Gregorian chant has its origin in the early Catholic Church. Musical instruments were excluded from early Christian worship, and text from Biblical passages was "chanted". By the 5th century, various types of chant were established. In time, Roman chant supplanted the other forms and became known as Gregorian chant.
The "modernization" of church music that followed the Second Vatican Council was accompanied by the modernization of the religious life of the Sisters. The traditional community life of prayer and contemplation was changed. It was replaced with an increased emphasis on activity in the world. This change resulted in the secularization of their lives. The Sisters left their cloisters and they exchanged their traditional religious habits for the garb of the secular world.
The Middle Ages extended from the fall of the Roman Empire in the West, at the end of the 4th century, to about the middle of the 5th century. Throughout the Middle Ages the dominant spiritual force was the Catholic Church and in the early Middle Ages the music of the Church was "PLAIN CHANT." It is called plain chant to distinguish it from polyphony or harmonized singing as well as from the musica mensurata which developed around the 12th or 13th century.
There is much that we do not know about the music of the Church in the first three centuries, but we do know that music was an important part of private devotion and official worship in the early church. We know that the texts used were taken from the psalms and canticles of the Bible. We know that hymns were composed for Church use using classical Greek and Hebrew poetic forms; and we know that from earlier times, musical instruments were excluded from Christian worship.
From the fourth century on, our knowledge is considerably greater. The edict of Milan in the year 313 provided the opportunity for growth and development of church music. By the 5th century various types of chant, including Ambrosian, Gallican, Mozarabic and Roman were established. And while they continued to develop, they were, for the most part, finalized in form in the days of Pop Gregory I. In time, the Roman chant supplanted the other forms of chant and is known as Gregorian chant.