Ash Wednesday derives its name from the placing of repentance ashes on the foreheads of participants to either the words "Repent, and believe in the Gospel" or the dictum "Remember that you are dust, and to dust you shall return." The ashes may be prepared by burning palm leaves from the previous year's Palm Sunday celebrations. Among Roman Catholics, Ash Wednesday is observed by fasting and repentance. In Anglican churches, the Book of Common Prayer also designates Ash Wednesday as a day of abstinence from particular foods.
Ashes are ceremonially placed on the heads of Christians on Ash Wednesday, either by being sprinkled over their heads or, in English-speaking countries, more often by being marked on their foreheads as a visible cross. The words (based on Genesis 3:19) used traditionally to accompany this gesture are, "Memento, homo, quia pulvis es, et in pulverem reverteris." ("Remember, man, that thou art dust, and to dust thou shalt return.") This custom is credited to Pope Gregory I the Great (c. 540–604). In the 1969 revision of the Roman Rite, an alternative formula (based on Mark 1:15) was introduced and given first place "Repent, and believe in the Gospel" and the older formula was translated as "Remember that you are dust, and to dust you shall return." The old formula, based on the words spoken to Adam and Eve after their sin, reminds worshippers of their sinfulness and mortality and thus, implicitly, of their need to repent in time. The newer formula makes explicit what was only implicit in the old.
Various manners of placing the ashes on worshippers' heads are in use within the Roman Rite of the Catholic Church, the two most common being to use the ashes to make a cross on the forehead and sprinkling the ashes over the crown of the head. Originally, the ashes were strewn over men's heads, but, probably because women had their heads covered in church, were placed on the foreheads of women. In the Catholic Church the manner of imposing ashes depends largely on local custom, since no fixed rule has been laid down. Although the account of Ælfric of Eynsham shows that in about the year 1000 the ashes were "strewn" on the head, the marking of the forehead is the method that now prevails in English-speaking countries and is the only one envisaged in the Occasional Offices of the Anglican Church of Papua New Guinea, a publication described as "noticeably Anglo-Catholic in character". In its ritual of "Blessing of Ashes", this states that "the ashes are blessed at the beginning of the Eucharist; and after they have been blessed they are placed on the forehead of the clergy and people." The Ash Wednesday ritual of the Church of England, Mother Church of the Anglican Communion, contains "The Imposition of Ashes" in its Ash Wednesday liturgy. On Ash Wednesday, the Pope, the Bishop of Rome, traditionally takes part in a penitential procession from the Church of Saint Anselm to the Basilica of Santa Sabina, where, in accordance with the custom in Italy and many other countries, ashes are sprinkled on his head, not smudged on his forehead, and he places ashes on the heads of others in the same way.
The Anglican ritual, used in Papua New Guinea states that, after the blessing of the ashes, "the priest marks his own forehead and then the foreheads of the servers and congregation who come and kneel, or stand, where they normally receive the Blessed Sacrament." The corresponding Catholic ritual in the Roman Missal for celebration within Mass merely states: "Then the Priest places ashes on the head of those present who come to him, and says to each one ..." Pre-1970 editions had much more elaborate instructions about the order in which the participants were to receive the ashes, but again without any indication of the form of placing the ashes on the head. The 1969 revision of the Roman Rite inserted into the Mass the solemn ceremony of blessing ashes and placing them on heads, but also explicitly envisaged a similar solemn ceremony outside of Mass. The Book of Blessings contains a simple rite. While the solemn rite would normally be carried out within a church building, the simple rite could appropriately be used almost anywhere. While only a priest or deacon may bless the ashes, laypeople may do the placing of the ashes on a person's head. Even in the solemn rite, lay men or women may assist the priest in distributing the ashes. In addition, laypeople take blessed ashes left over after the collective ceremony and place them on the head of the sick or of others who are unable to attend the blessing. (In 2014, Anglican Liverpool Cathedral likewise offered to impose ashes within the church without a solemn ceremony.)
In addition, those who attend such Catholic services, whether in a church or elsewhere, traditionally take blessed ashes home with them to place on the heads of other members of the family, and it is recommended to have envelopes available to facilitate this practice. At home the ashes are then placed with little or no ceremony.