The Immaculate Conception of the Virgin Mary was celebrated by the Church with a feast on December 8th for centuries before it was formally defined as a dogma of the Faith by Bl. Pope Pius IX in 1854. Up until that point, there were various version of the Divine Office and Mass for the feast used in various places, and this continued to be the case for nine years after the definition. In 1863, however, the Pope promulgated a new version of both which supplanted all others, and which are part of the usus antiquior to this day. During the octave of the feast, a series of the readings for Matins are taken from his bull Ineffabilis Deus, the dogmatic proclamation of 1854. It is pleasant to remember that there was a time when papal bulls were written in such beautiful Latin that the Church might rightly deem them worth to be incorporated into her official prayer books. Here is just a small sample, the opening sentence of 116 words, which is long enough to occupy a full lesson on its own in the breviary.
“Ineffabilis Deus, cujus viæ misericordia et veritas, cujus voluntas omnipotentia, et cujus sapientia attingit a fine usque ad finem fortiter, et disponit omnia suaviter, cum ab omni æternitate præviderit luctuosissimam totius humani generis ruinam ex Adami transgressione derivandam, atque in mysterio a sæculis abscondito, primum suæ bonitatis opus decreverit per Verbi incarnationem sacramento occultiore complere, ut contra misericors suum propositum homo diabolicæ iniquitatis versutia actus in culpam non periret, et quod in primo Adamo casurum erat, in secundo felicius erigeretur, ab initio et ante sæcula unigenito Filio suo Matrem, ex qua caro factus in beata temporum plenitudine nasceretur, elegit atque ordinavit, tantoque præ creaturis universis est prosecutus amore, ut in illa una sibi propensissima voluntate complacuerit.
(The Proclamation of the Dogma of the Immaculate Conception, by Francesco Podesti, 1859-61.)
The ineffable God whose ways are mercy and truth, whose will is omnipotence, and whose wisdom reacheth mightily from one end (i.e. of creation) to another, and sweetly ordereth all things, (Wisdom 8, 1), since from all eternity he foresaw the most sorrowful ruin of the whole human race that would derive from the transgression of Adam, and, in a mystery hidden from the ages, determined to fulfill the first work of His goodness through the incarnation of the Word, in a more hidden secret, to the end that man, who against his merciful purpose had been driven by the fraud of the devil to sin, might not perish, and that what was to fall in the first Adam, might be raised up the more happily in Christ, from the beginning and before the ages chose and arranged for His Only-begotten Son a Mother, from whom, having become flesh, He might be born in the blessed fullness of time, and honored Her above all other creatures with with such great love that in Her alone He was well-pleased with a most ready will.”
And likewise, the single sentence of over 120 words towards the end of the bull that contains the formal definition:
“…postquam numquam intermisimus in humilitate et jejunio privatas nostras et publicas Ecclesiæ preces Deo Patri per Filium ejus offerre, ut Spiritus Sancti virtute mentem nostram dirigere et confirmare dignaretur, implorato universæ cælestis curiæ præsidio, et advocato cum gemitibus Paraclito Spiritu, eoque sic aspirante; ad honorem sanctæ et individuæ Trinitatis, ad decus et ornamentum Virginis Deiparæ, ad exaltationem fidei catholicæ et christianæ religionis augmentum, auctoritate Domini nostri Jesu Christi, beatorum Apostolorum Petri et Pauli, ac nostra, declaramus, pronuntiamus et definimus: doctrinam quæ tenet beatissimam Virginem Mariam in primo instanti suæ Conceptionis fuisse singulari omnipotentis Dei gratia et privilegio, intuitu meritorum Christi Jesu Salvatoris humani generis, ab omni originalis culpæ labe præservatam immunem, esse a Deo revelatum, atque idcirco ab omnibus fidelibus firmiter constanterque credendam.
After in having never ceased to off to God the Father though His Son our private prayers and the public prayers of the Church, in fasting and humility, that he might deign to guide and confirm our mind by the power of the Holy Spirit, having implored the aid of the whole court of heaven, and called with groanings upon the Spirit, the Paraclete, and with His inspiration: for the honor of the holy and undivided Trinity, for the praise and glory of the Virgin Mother of God, for the exaltation of the Catholic Faith, and the increase of the Christian religion; by the authority of our Lord Jesus Christ, of the Blessed Apostles Peter and Paul, and Our own, we declare, pronounce and define that doctrine which holds that the most blessed Virgin Mary was, in the first instant of her Conception, preserved, by a singular grace and privilege of Almighty God, in view of the merits of Christ Jesus, the Savior of the human race mankind, preserved free from every stain of original sin, is a doctrine revealed by God, and therefore to be believed firmly and constantly by all the faithful.”