In the early Church, the word "acolythus" was used to indicate those men who ministered at the Mass and other liturgies. They assisted the priests and the deacons with whatever was required during the Mass. We have records from the 500s that testify to the "ordination" of acolytes. Ordination meant two things: 1) that the acolyte was officially given a role in the community on behalf of the church, and 2) that the man was given an place within an "order" of different ministries, which were called "minor orders" (porter, lector, exorcist, acolyte, subdeacon, deacon, priest, bishop). These minor orders were what seminarians received as ministerial preparation throughout their years in seminary. These rites of ordination continued until 1972 (Motu proprio Ministeria quædam), when Pope Pius VI restructured these ministries and limited them to "lector" and "acolyte".
Though that is a much abbreviated etymology and history, it swiftly brings us to present day. Today, the word acolyte properly means those men who are duly instituted "for service at the altar and to assist the Priest and Deacon. It is his place principally to prepare the altar and the sacred vessels and, if necessary, to distribute the Eucharist to the faithful as an extraordinary minister" ("General Instruction of the Roman Missal", no. 98, henceforth GIRM). "Duly instituted" means that a bishop has questioned the man and has assigned to him this liturgical role which he will officially exercise on behalf of the church. Therefore, when there is an instituted acolyte present, he serves the Mass or assists at the liturgy in an official capacity and on behalf of the Church, because the Church has deputed him to do so.
In a parish setting, however, there are usually not instituted acolytes around, unless there is a seminarian there who has been instituted. Therefore, young men can assist at the Mass and are called "acolytes" because they substitute for an instituted acolyte. For the most part, they would do the same things that an instituted acolyte does:
"The functions that the acolyte may carry out are of various kinds and several may occur at the same moment. Hence, it is desirable that these duties be suitably distributed among several acolytes.
…In the procession to the altar, the acolyte may carry the cross, walking between two ministers with lighted candles. Upon reaching the altar, however, … he puts it away in a dignified place. Then he takes his place in the sanctuary.
Through the entire celebration, it is for the acolyte to approach the Priest or the Deacon, whenever necessary, in order to present the book to them and to assist them in any other way required. Thus it is appropriate that, in so far as possible, the acolyte should occupy a place from which he can easily carry out his ministry either at the chair or at the altar.
In the absence of a Deacon, after the Universal Prayer and while the Priest remains at the chair, the acolyte places the corporal, the purificator, the chalice, the pall, and the Missal on the altar. Then, if necessary, the acolyte assists the Priest in receiving the gifts of the people and, if appropriate, brings the bread and wine to the altar and hands them to the Priest. If incense is being used, the acolyte presents the thurible to the Priest and assists him while he incenses the offerings, the cross, and the altar. Then the acolyte incenses the Priest and the people.
A duly instituted acolyte, as an extraordinary minister, may, if necessary, assist the Priest in distributing Communion to the people. If Communion is given under both kinds, in the absence of a Deacon, the acolyte administers the chalice to the communicants or holds the chalice if Communion is given by intinction.
Likewise, after the distribution of Communion is complete, a duly instituted acolyte helps the Priest or Deacon to purify and arrange the sacred vessels. In the absence of a Deacon, a duly instituted acolyte carries the sacred vessels to the credence table and there purifies them, wipes them, and arranges them as usual.
After the celebration of Mass, the acolyte and other ministers return together with the Deacon and the Priest in procession to the sacristy, in the same manner and in the same order in which they entered" (GIRM, nos. 187-193).
These are, most generally, the duties of an acolyte for a regular Sunday Mass. I have highlighted with italics the places that the GIRM makes a distinction between what an acolyte and an instituted acolyte does to show that there is a difference between one who officially ministers on behalf of the Church and one who substitutes his role.
Altogether, then, the acolyte serves in a special way at the Mass and other liturgies. It is a special place that requires prayer, reverence, and a decent knowledge of the Mass. In upcoming trainings for the acolytes, we will be going over the basic structure of the Mass and the ways in which the young men will be assisting the priests.
Don't forget: Acolyte Orientation will be on August 10 from 11am to 1:30pm. We will begin in the church and lunch will be provided. Parents are more than welcome to join us. Tell us your coming by emailing firstname.lastname@example.org.