Catholic Encyclopedia (1913)/Ashes
It is not easy to arrive at the fundamental conception of the liturgical use of ashes. No doubt our Christian ritual has been borrowed from the practice of the Jews, a practice retained in certain details of synagogue ceremonial to this day, but the Jewish custom itself needs explanation. A number of passages in the Old Testament connect ashes (efer) with mourning, and we are told that the mourner sat or rolled himself in, sprinkled his head or mingled his food with, "ashes", but it is not clear whether in these passages we ought not rather to translate efer as dust. The same phrases are used with the word afar which certainly means dust. It may be that the dust was originally taken from the grave, in token that the living felt himself one with the dead, or it may be that humiliation and the neglect of personal cleanliness constituted the dominant idea; for a similar manifestation of grief was undoubtedly familiar among Aryan peoples, e.g. in Homer (Iliad, XVIII, 23). It seems less probable that the cleansing properties of ashes (though this also has been proposed) are taken as significant of moral purification. The chief foundation for this last suggestion is the Rite of the Red Heifer (Num., xix, 17) in which the ashes of the victim when mixed with water had the ceremonial efficacy of purifying the unclean (cf. Heb., ix, 13).
Be this as it may, Christianity at an early date undoubtedly adopted the use of ashes as symbolical of penance. Thus Tertian prescribes that the penitent must "live without joy in the roughness of sackcloth and the squalor of ashes" (De Pœnitentiâ, x); and many similar passages might be quoted from St. Cyprian and other early Fathers. Eusebius in his account of the apostasy and reconciliation of Natalis describes him as coming to Pope Zephyrinus clothed in sackcloth and sprinkled over with ashes (spodon katapasamenon, Hist. Eccles., V, 28). This was the normal penitential garb, and n the expulsion of those sentenced to do public penance, as given in early pontificals, the sprinkling of their heads with ashes always plays a prominent part. Indeed the rite is retained in the Pontificale Romanum to this day. With this garb of penance we must undoubtedly connect the custom, so frequent n the early Middle Ages, of laying a dying man on the ground upon sackcloth sprinkled with ashes when about to breathe his last. Early rituals direct the priest to cast holy water upon him, saying, "Remember that thou are dust and unto dust the shall return." After which he asked: "Art thou content with sackcloth and ashes in testimony of thy penance before the Lord, in the day of judgment?" And the dying man answered: "I am content.: Ashes are also liturgically used n the rite of the dedication of a church, first upon which all the alphabet is written in Greek and Latin letters, and secondly to mix with oil and wine in the water which is specially blessed for the consecration of the altars. This use of ashes is probably older than the eighth century.
Kaulen, in Kirchenlex., s. v. Asche; Cabrol, Livre de la priere antique (Paris, 1900), 347-348; Jewish Encyclopedia, s. v. Ashes; Lesêtre in Vig., Dict. de la Bible, s. v. Cendres.