ANTIPHONY, a species of psalmody in which the choir or congregation, being divided into two parts, sing alternately in a manner suggested by the derivation of the word (Gr. avri, and ccovi, a voice). The peculiar structure of the Hebrew psalms renders it probable that the antiphonal method originated in the service of the ancient Jewish Church. According to the historian Socrates, its introduction into Christian worship was due to Igna tius (d. A.D. I15) who in a vision had seen the angels singing in alternate choirs. In the Latin Church it was not practised until more than two centuries later, when it was introduced by Ambrose, bishop of Milan. The antiphonary still in use in the Roman Catholic Church was compiled by Gregory the Great (A.D. S9o).