The Latin incipit or opening phrase for Ps 98 which in earlier Prayer Books began "O sing unto the Lord a new song." Objection was raised to use in the 1549 Prayer Book of the "Gospel canticles" (Benedictus, Magnificat, and Nunc dimittis) by some who believed that these songs of Zechariah, Mary, and Simeon could not properly be sung by others. In the 1552 revision of the Prayer Book, a psalm was provided as an alternative to each of these gospel canticles. Ps 98, Cantate Domino, was provided as the alternative to the Magnificat at Evening Prayer.
Glossary definitions provided courtesy of Church Publishing Incorporated, New York, NY,(All Rights reserved) from "An Episcopal Dictionary of the Church, A User Friendly Reference for Episcopalians," Don S. Armentrout and Robert Boak Slocum, editors.