On the feast of Saint Damasus I Pope and Confessor...

This great Pontiff comes before us in the Liturgical Year, not to bring us tidings of Peace, as St. Melchiades did, but as one of the most illustrious defenders of the great Mystery of the Incarnation. He defends the faith of the Universal Church in the divinity of the Word, by condemning, as his predecessor Liberius had done, the acts and the authors of the celebrated Council of Rimini. With his sovereign authority, he bears witness to the teaching of the Church regarding the Humanity of Jesus Christ, and condemned the heretic Apollinaris, who taught that Jesus Christ had only assumed the flesh and not the soul of man. He commissioned St. Jerome to make new translation of the New Testament from the Greek, for the use of the Church of Rome here, again, giving further proof of the faith and love which he bore to the Incarnate Word. Let us honour this great Pontiff, whom the Council of Chalcedon calls the ornament and support of Rome by his piety. St. Jerome, too, who looked upon St. Damasus as his friend and patron, calls him a man of the greatest worth whose equal could not be found, well versed in the holy Scriptures, and a virgin Doctor of the virgin Church.

The Legend of the Breviary gives us brief account of his life. [From 1570, Saint Damasus is only commemorated in the Roman Office, so this hagiographic lesson is no longer read in it; Dom Prosper may have been consulting the Romano-Gallican breviary? I don't know.] 

Damasus Hispanus, vir egregius et eruditus in Scripturis, indicto primo Constantinopolitano Concilio, neferiam Eunomii et Macedonii haeresim exstinxit. Idem Ariminensem conventum Liberio jam ante rejectum, iterum condemnavit in quo, ut scribit sanctus Hieronymus, Valentis potissimum et Ursascii fraudibus damnatio Nicenae fidei conclamata fuit, et ingemiscens orbis terrarum, se Arianum esse miratus est. Basilicas duas aedificavit alteram sancti Laurentii nomine ad theatrum Pompeii, quam maximis muneribus auxit, eique domos, et praedia attribuit: alteram via Ardeatina ad Catacumbas.
Platoniam etiam, ubi corpora sanctorum Petri et Pauli aliquandiu jacuerunt, dedicavit, et exornavit elegantibus versibus. Idemque prosa, et versu scripsit de Virginitate, multaque alia metro edidit. Poenam talionis constituit iis, qui alterum falsi criminis accusassent. Statuit, ut quod pluribus jam locis erat in usu, Psalmi per omnes Ecclesias die noctuque ab alternis canerentur; et in fine cujusque Psalmi diceretur Gloria Patri, et Filio, et Spiritui Sancto. Ejus jussu sanctus Hieronimus novum Testamentum Graecae fidei reddidit. Quum Ecclesiam rexisset annos decem et septem, menses duos, dies viginti, et habuisset Ordinationes quinque mense Decembri, quibus creavit Presbyteros triginta unum, Diaconos undecim, Episcopos per diversa lex sexaginta duos; virtute, doctrina, ac prudentia clarus, prope octogenarius, Theodosio seniore imperante, obdormivit in Domino, et via Ardeatina una cum matre et sorore sepultus est in Basilica, quam ipse aedificaverat. Illius reliquiae postea translatae sunt in ecclesiam sancti Laurentii, ab ejus nomine in Damaso vocatam.

Holy Pontiff Damasus, during thy life on earth, thou wast the Light, which guided the children of the Church for thou didst teach them the mystery of the Incarnation, and didst guard them against those perfidious doctrines, wherewith hell ever strives to corrupt that glorious Symbol of our faith, which tells us of God's infinite mercy towards us, and of the sublime dignity of man thus mercifully redeemed. Seated on the Chair of Peter, thou didst confirm thy brethren, and thy faith failed not for Jesus had prayed to his Father for thee. We rejoice at the infinite recompense with which this divine Prince of Pastors has rewarded the unsullied purity of thy faith, thou virgin Doctor of the virgin Church that we could have a ray of that light which now enables thee to see Jesus in his glory. Pray for us, that we may have light to see him, and know him, and love him under the humble guise in which he is so soon to appear to us. Obtain for us the science of the sacred Scriptures, in which thou wast so great a Master; and docility to the teachings of the Bishop of Rome, to whom, in the person of St. Peter, Christ has said, Launch out into the deep! Obtain also for all Christians, thou the successor of this Prince of the Apostles, that they be animated with those sentiments, which St. Jerome thus describes in one of his letters addressed to thee: 'It is the Chair of Peter that I will consult, for from it do I derive that faith, which is the food of my soul. I will search for this precious pearl, heeding not the vast expanse of sea and land which I must pass over. Where the body is, there shall the eagles be gathered together. It is now in the West that the Sun of justice rises. I ask the Victim of salvation from the Priest, and from the Shepherd, the protection of the sheep. On that rock I know the Church is built. He that eats the Lamb in any house but this, is profane. He that is not in Noah's Ark, shall perish in the waters of the deluge. I know not Vitalis, reject Meletius, pass by Paulinus. He that gathers not with thee, Damasus, scatters; for he that is not of Christ, is of Antichrist."
Let us contemplate our divine Saviour in the womb of his most holy Mother Mary. Let us, together with the holy Angels, adore him in this state of profound humiliation, to which his love for us has brought him. See him there offering himself to his Father for the redemption of mankind, and commencing at once to fulfil the office of our Mediator, which he has taken upon himself. What an excess of love is this of our Jesus, that he is not satisfied with having humbled himself in assuming our nature, and which alone would have sufficed to redeem million worlds! The eternal Son of God wills to remain, as other children, nine months in his Mother's womb after that, to be born in poverty, to live a life of labour and suffering, and to be obedient to death even to the death of the Cross. O Jesus, mayest thou be praised and loved by all creatures for this thy immense love of us Thou hast come down from heaven the Victim that art to take the place of all those which were hitherto offered, but which could not efface man's sin. At length, the earth possesses its Saviour, though as yet unseen. No, God will not curse the earth, which, though covered with crime, is rich in such treasure as this. Still repose, Jesus, in the chaste womb of Mary, that living Ark which contains the true Manna sent for the food of man. But the time is approaching for thee to leave this loved sanctuary. The tender love which thou hast received from Mary, must be changed for the malice wherewith men will treat thee; yet it must needs be that thou be born on the day which thou thyself hast decreed: it is the will of thy eternal Father, it is the expectation of the world, it is the salvation of all who shall love thee.