Complete Encyclopaedia of Music/A/Ambrose, St

Ambrose, St., introduced what is called the "Cantus Ambrosianus" into his church at Milan, about the end of the fourth century. He is said by St. Augustine to have brought this manner of singing from Greece. Those who have written on the subject agree that St. Ambrose only used the four authentic modes, and that the four plagal were afterwards added by St. Gregory.