The Wednesday after Quinquagesima Sunday, which is the first day of the Lenten fast. The name dies cinerum (day of ashes) which it bears in the Roman Missal is found in the earliest existing copies of the Gregorian Sacramentary and probably dates from at least the eighth century. On this day all the faithful according to ancient custom are exhorted to approach the altar before the beginning of Mass, and there the priest, dipping his thumb into ashes previously blessed, marks the forehead -- or in case of clerics upon the place of the tonsure -- of each the sign of the cross, saying the words: "Remember man that thou art dust and unto dust thou shalt return." The ashes used in this ceremony are made by burning the remains of the palms blessed on the Palm Sunday of the previous year. In the blessing of the ashes four prayers are used, all of them ancient. The ashes are sprinkled with holy water and fumigated with incense. The celebrant himself, be he bishop or cardinal, receives, either standing or seated, the ashes from some other priest, usually the highest in dignity of those present. In earlier ages a penitential procession often followed the rite of the distribution of the ashes, but this is not now prescribed.
There can be no doubt that the custom of distributing the ashes to all the faithful arose from a devotional imitation of the practice observed in the case of public penitents. But this devotional usage, the reception of a sacramental which is full of the symbolism of penance (cf. the cor contritum quasi cinis of the "Dies Irae") is of earlier date than was formerly supposed. It is mentioned as of general observance for both clerics and faithful in the Synod of Beneventum, 1091 (Mansi, XX, 739), but nearly a hundred years earlier than this the Anglo-Saxon homilist Ælfric assumes that it applies to all classes of men. "We read", he says, in the books both in the Old Law and in the New that the men who repented of their sins bestrewed themselves with ashes and clothed their bodies with sackcloth. Now let us do this little at the beginning of our Lent that we strew ashes upon our heads to signify that we ought to repent of our sins during the Lenten fast. And then he enforces this recommendation by the terrible example of a man who refused to go to church for the ashes on Ash Wednesday and who a few days after was accidentally killed in a boar hunt (Ælfric, Lives of Saints, ed. Skeat, I, 262-266). It is possible that the notion of penance which was suggested by the rite of Ash Wednesday was was reinforced by the figurative exclusion from the sacred mysteries symbolized by the hanging of the Lenten veil before the sanctuary.
- The Catholic Encyclopedia


Blessing of the Ashes

Before the Mass, the ashes obtained by burning the branches of olive and other trees blessed the preceding year, are now blessed. When None has been said in choir, the priest, vested in alb, stole, and purple cope, stands at the epistle corner of the altar, on which is placed a vessel containing the ashes to be blessed. The choir sings the following antiphon:

Antiphon
Hear us, O Lord, for Thy mercy is kind: look upon us, O Lord, according to the multitude of Thy tender mercies. -- (Ps. 68. 2). Save me, O God: for the waters are come in even unto my soul. V.: Glory be to the Father . . . -- Hear us, O Lord, for Thy mercy is kind...

Afterwards the priest, standing at the epistle side, without turning towards the people, with his hands joined, says:

V.: The Lord be with you.
R.: And with thy spirit.

Let us pray. -- O almighty and everlasting God, spare those who are penitent, be merciful to those who implore Thee; and vouchsafe to send Thy holy Angel from heaven, to bless † and hal†low these ashes, that they may be a wholesome remedy to all who humbly implore Thy holy Name, and who accuse themselves, conscious of their sins, deploring their crimes before Thy divine mercy, or humbly and earnestly beseeching Thy sovereign goodness: and grant through the invocation of Thy most holy Name that whosoever shall be sprinkled with them for the remission of their sins may receive both health of body and safety of soul. Through Christ our Lord.
R.: Amen.

Let us pray. -- O God, who desirest not the death, but the repentance of sinners, look down most graciously upon the frailty of human nature; and in Thy goodness vouchsafe to bless † these ashes which we purpose to put opon our heads in token of our lowliness and to obtain forgiveness: so that we who know that we are but ashes, and for the demerits of our wickedness are to return to dust, may deserve to obtain of Thy mercy, the pardon of all our sins, and the rewards promised to the penitent. Through Christ our Lord.
R.: Amen.

Let us pray. -- O God, who art moved by humiliation, and appeased by satisfaction: incline the ear of Thy goodness to our prayers and mercifully pour forth upon the heads of Thy servants sprinkled with these ashes the grace of Thy blessing: that Thou mayest both fill them with the spirit of compunction, and effectually grant what they have justly prayed for: and ordain that what Thou hast granted may be permanently established and remain unchanged. Through Christ our Lord.
R.: Amen.

Let us pray. -- O almighty and everlasting God, who didst vouchsafe Thy healing pardon to the Ninivites doing penance in sackcloth and ashes, mercifully grant that we may so imitate them in our outward attitude as to follow them in obtaining forgiveness. Through Christ our Lord .. .
R.: Amen.

The priest then sprinkles the ashes thrice with holy water, singing the anthem Asperges me . . . and incenses them thrice. After which, having first received the ashes on his own head, from the highest in dignity of the clergy, he proceeds to place them, in the form of across, on the heads or foreheads of the clergy and people, saying to each:

(Gen. 3. 19) Remember, man, that thou art dust, and unto dust thou shalt return.

Meanwhile the choir sings the following anthems and responses:

Antiphon

Let us change our garments for ashes and sackcloth: let us fast and lament before the Lord: for plenteous in mercy is our God to forgive our sins.

Between the porch and the altar, the priests, the Lord's ministers, shall weep and shall say: Spare, O Lord, spare Thy People: and close not the mouths of them that sing to Thee, O Lord.

R.: Let us amend for the better in those things in which we have sinned through ignorance; lest suddenly overtaken by the day of death, we seek space for repentance and are not able to find it. * Attend, O Lord, and have mercy: for we have sinned against Thee.

V.: (Ps. 78. 9). Help us, O God, our savior: and for the glory of Thy Name, O Lord, deliver us. * Attend, O Lord . . . V.: Glory be to the Father, and to the Son, and to the Holy Ghost. * Attend...

When all have received the ashes, the priest says:

V.: The Lord be with you.
R.: And with thy spirit.

Let us pray. -- Grant us, O Lord, to begin with holy fasts the campaign of our Christian warfare: that, as we do battle with the spirits of evil, we may be protected by the help of self-denial. Through Christ our Lord.
R.: Amen.

Mass Propers

Introit
Thou hast mercy upon all, O Lord, and hatest none of the things which Thou hast made, overlooking the sins of men for the sake of repentance, and sparing them: because Thou art the Lord our God. -- (Ps. 56. 2). Have mery on me, O God, have mercy on me: for my soul trusteth in Thee. V.: Glory be to the Father . . . -- Thou hast mercy upon all, O Lord...

Collect
Grant, O Lord, to Thy faithful people, that they may undertake with fitting piety the venerable solemnities of fasting, and complete them with steadfast devotion. Through our Lord Jesus Christ, Thy Son, who liveth and reigneth with Thee in the unity of the Holy Ghost...

Epistle
Thus saith the Lord: Be converted to Me with all your heart, in fasting and in weeping and in mourning. And rend your heats and not your garments, and turn to the Lord your God: for He is gracious and merciful, patient and rich in mercy, and ready to repent of the evil. Who knoweth but He will return and forgive and leave a blessing behind Him, sacrifice and libation to the Lord your God? Blow the trumpet in Sion, sanctify a fast, call a solemn assembly, gather together the people, sanctify the Church, assemble the ancients, gather together the little ones and them that suck at the breasts: let the bridegroom go forth from his bed and the bride out of her bride chamber. Between the porch and the altar the priests, the Lord's ministers, shall weep and shall say: Spare, O Lord, spare Thy people; and give not Thine inheritance to reproach, that the heathen should rule over them. Why should they say among the nations: Where is their God? The Lord hath been zealous for His land, and hath spared His people. And the Lord answered and said to His people: behold I will send you corn and wine and oil, and you shall be filled with them: and I will no more make you a reproach among the nations: saith the Lord almighty.

Gradual
Have mercy on me, O Lord, have mercy on me: for my soul trusteth in Thee. V.: He hath sent from heaven and delivered me: He hath made them a reproach that trod upon me.

Tract
O Lord, repay us not according to the sins we have committed, nor according to our iniquities. V.: (Ps. 78. 8, 9) O Lord, remember not our former iniquities, let Thy mercies speedily prevent us: for we are become exceeding poor.
[Here kneel.]
V.: Help us, O God, our Savior: and for the glory of Thy Name, O Lord, deliver us: and forgive us our sins for Thy Name's sake.

Gospel
At that time Jesus said to His disciples: When you fast, be not as the hypocrites, sad. For they disfigure their face, that they may appear unto men to fast. Amen I say to you, they have received their reward. But thou, when thou fastest, anoint thy head and wash thy face, that thou appear not to men to fast, but to thy Father who is in secret: and thy Father who seeth in secret will repay Thee. Lay not up to yourselves treasures on earth: where the rust and moth consume, and where thieves break through and steal. But lay up to yourselves treasures in heaven: where neither the rust nor moth doth consume, and where thieves do not break through nor steal. For where thy treasure is, there is thy heart also.

Offertory
I will extol Thee, O Lord, for Thou hast upheld me, and hast not made my enemies to rejoice over me: O Lord, I have cried to Thee, and Thou hast healed me.

Secret
Fit us, we beseech Thee, O Lord, to offer worthily these gifts, by which we celebrate the opening of this venerable Mystery. Through our Lord Jesus Christ, Thy Son, who liveth and reigneth with Thee in the unity of the Holy Ghost...

Preface
It it truly meet and just, right and for our salvation, that we should at all times, and in all places, give thanks unto Thee, O holy Lord, Father almighty, everlasting God; Who by this bodily fast, dost curb our vices, dost lift up our minds and bestow on us strength and rewards; through Christ our Lord. Through whom the Angels praise Thy Majesty, the Dominations worship it, the Powers stand in awe. The Heavens and the heavenly hosts together with the blessed Seraphim in triumphant chorus unite to celebrate it. Together with these we entreat Thee that Thou mayest bid our voices also to be admitted while we say with lowly praise:

Communion
He that shall meditate day and night on the law of the Lord, shall bring forth his fruit in due season.

Postcommunion
May the Sacraments we have received afford us help, O Lord, that our fasts may be pleasing unto Thee, and profitable unto us for healing. Through our Lord Jesus Christ, Thy Son, who liveth...

Prayer Over The People
Let us pray. Bow down your heads before God. -- Look graciously, O Lord, upon us who bow down before Thy majesty: that we who have been refreshed by Thy divine Gift may ever be sustained by Thy heavenly aids. Through our Lord Jesus Christ, Thy Son...

The Divine Office for today is available here: http://www.breviary.net/propseason/lent/pr...nlent0ash04.htm

A Homily by St. Augustine the Bishop

From these precepts it is evident that our every action should be directed towards the attainment of an interior life, which alone giveth true happiness. For if contrariwise we seek our reward in outward things, we shall be conformed to the fashion of this world, and thus forfeit God's promise of happiness, to wit, that we shall be conformed to the image of his Son. Such happiness, inasmuch as it concerneth inward things, is all the more certain and enduring. Howbeit, the special teaching of this passage is this : That vainglory can come forth, not only from worldly elegance and human pretensions, but even from a condition of sad countenance and dirty disfigurement. Furthermore, the latter kind of vainglory is the more dangerous, in that it deceiveth under the pretence of an humble service of God.
On the one hand, whosoever sheweth unbridled indulgence, whether in bodily comforts and dress, or in other forms of elegance, thereby standeth manifestly convicted as a follower of the pomps of this world. Nor doth such an one, by his pretence of godliness, deceive anybody. On the other hand, whosoever from choice, and not of necessity, professeth Christianity in such wise as to draw attention unto himself by reason of his seeming humility, or his particular disregard for outward things, this man is to be judged from the fashion of his other behaviour, as to whether therein he sheweth a desire for mortification, or rather for vainglory. For the Lord biddeth us beware of wolves in sheep's clothing. Rather, as he saith, by their fruits shall ye know them.
Now here is the test of the seeming godliness of such folk. When some adversity bringeth upon them the loss of the advantages which they had gained, or sought to gain, by their profession of godliness, then it must needs appear whether they be wolves in sheep's clothing, or sheep in their own. Nevertheless, a Christian should not seek to tickle the fancy of other folk by a parade of elegance, on the plea that hypocrites do seek to beguile the unwary by a display of frugality. For sheep should not lay aside their own clothing because wolves do sometimes falsely assume the same.

A vínculis peccatórum nostrórum absólvat nos omnípotens et miséricors Dóminus. Amen.