19 This peace truly so called We wish for you from our heart, Venerable Brethren, on this very day on which by the Divine bounty the fiftieth year of Our Priesthood is completed, and as the sweet festival of the Nativity of Our Lord Jesus Christ approaches, which may be called the mystery of peace approaches, we with fervent prayer supplicate for that gift for him who is hailed as the Prince of Peace. And with our mind raised by these thoughts a joyful and firm hope as an omen of divine gifts, and as a pledge of Our affection to you, Venerable Brethren, and to your clergy and people - that is, to all our most beloved Catholic family - We impart the Apostolic Benediction most loving in the Lord. Given at St. Peter's Rome, on the twentieth day of December, 1929, the eighth year of Our Pontificate .
Source: Mens Nostra (Vatican.va)