85 In the meantime, buoyed up by the hope of richer and more joyous fruits which We are confident will come from this exhortation of Ours, as a testimony of Our good will and as an omen of heavenly gifts to each one of you, venerable brethren, to the flock entrusted to your care and to those who observe Our wishes and work to promote sacred music, with abundant charity, We impart the Apostolic Benediction. Given at St. Peter's in Rome, December 25, on the feast of the Nativity of Our Lord Jesus Christ, in the year 1955, the 17th of Our Pontificate.
Source: Musicae Sacrae (Vatican.va)