St. Ambrose’s innovations soon found favor elsewhere. Antiphonal psalmody was introduced into the service at Rome by Pope Celestine (pope from 422 to 432), and in a short time was quite generally adopted throughout the domains of the church. St. Augustine (354-430), who was a friend of St. Ambrose and a collaborator with him, and who is said to have made a collection of Ambrosian melodies for the use of the church, bears touching testimony to their emotional effect: ‘How I wept at thy hymns and canticles, pierced to the quick by the voices of thy melodious church! Those voices flowed into my ears, and the truth distilled into my heart, and thence there streamed forth a devout emotion, and my tears ran down, and happy was I therein.’ (St. Augustine, ‘Confessions,’ Book 9, chap. 6.) The so-called Ambrosian collection vied in importance with the Gregorian for several centuries and many of its finest features were undoubtedly incorporated into the later and more comprehensive collection. So important a place does St. Ambrose fill in the history of ecclesiastical music that the term Ambrosian is still applied to usages, both liturgical and musical, of the Church of Milan, which distinguish its service in certain respects from the Roman service, and which are supposed to have been originated by the great Milanese bishop. After St. Ambrose the next prelate to impress himself profoundly on the course of development of church-music was Pope Gregory the Great (pope from 590 to 604). While recent research[1] has proved beyond doubt that a multitude of reforms and innovations attributed to him by mediæval legends and repeated by later history belong in reality to a much later period, it is well established that he manifested an enthusiastic and well-directed interest in the music of the service, that he introduced many corrective measures to curb the growing danger of secularizing church-music through the use of unauthorized embellishments and licenses in singing the chants, and that he brought about a thorough and far-reaching reorganization of the singing schools. When he became pope in 590, the liturgy was practically completed as far as its actual material was concerned. Since the earliest practices of the church had encouraged a musical liturgy, he found in actual use a vast number of chants and musical settings for various parts of the services. These musical settings differed in different localities. In conformity with his definitely conceived policy of establishing in reality one universal church for all peoples and races, with centralized power and highly-organized form of government, he set about to accomplish a definite systematization and an authoritative organization of all liturgic functions, together with the necessarily similar regulation of the music associated with the liturgy. This reform was in the nature of a codification of existing material, and while he did not finish the great work, he brought it