In religion, a relic is an object or article of religious significance from the past.
It usually consists of the physical remains of a saint or the personal effects of the saint or venerated person preserved for purposes of veneration as a tangible memorial.
Relic derives from the Latin reliquiae, meaning "remains", and a form of the Latin verb relinquere, to "leave behind, or abandon".
A reliquary is a shrine that houses one or more religious relics.
CLASSIFICATIONS AND PROHIBITIONS IN THE CATHOLIC CHURCH.
In Catholic theology, sacred relics must not be worshipped, because only God is worshipped and adored. Instead, the veneration given to them was "dulia". Saint Jerome declared, "We do not worship, we do not adore, for fear that we should bow down to the creature rather than to the Creator, but we venerate the relics of the martyrs in order the better to adore Him whose martyrs they are."
Up until 2017, the Catholic church divided relics into three classes:
First-class relics: items directly associated with the events of Christ's life (manger, cross, etc.) or the physical remains of a saint (a bone, a hair, skull, a limb, etc.). Traditionally, a martyr's relics are often more prized than the relics of other saints. Parts of the saint that were significant to that saint's life are more prized relics. For instance, King St. Stephen of Hungary's right forearm is especially important because of his status as a ruler. A famous theologian's head may be his most important relic; the head of St. Thomas Aquinas was removed by the monks at the Cistercian abbey at Fossanova where he died. If a saint travelled often, then the bones of his feet may be prized. Catholic teaching prohibits relics to be divided up into small, unrecognizable parts if they are to be used in liturgy (i.e., as in an altar; see the rubrics listed in Rite of Dedication of a Church and an Altar).
Second-class relics: items that the saint owned or frequently used, for example, a crucifix, rosary, book, etc. Again, an item more important in the saint's life is thus a more important relic. Sometimes a second-class relic is a part of an item that the saint wore (a shirt, a glove, etc.) and is known as ex indumentis ("from the clothing").
Third-class relics: any object that has been in contact with a first- or second-class relic. Most third-class relics are small pieces of cloth, though in the first millennium oil was popular; the Monza ampullae contained oil collected from lamps burning before the major sites of Christ's life, and some reliquaries had holes for oil to be poured in and out again. Many people call the cloth touched to the bones of saints "ex brandea". But ex brandea strictly refers to pieces of clothing that were touched to the body or tombs of the apostles. It is a term that is used only for such; it is not a synonym for a third-class relic.
In 2017, the Congregation for the Causes of Saints abolished the relics of the third degree, introducing a two-stage scale of classification of relics: significant (insigni) and non-significant (non insigni) relics. The first are the bodies or their significant parts, as well as the entire contents of the urn with the ashes preserved after cremation. The second includes small fragments of the bodies, as well as objects used by saints and blesseds.
The sale or disposal by other means of "sacred relics" (meaning first and second class) without the permission of the Apostolic See is nowadays strictly forbidden by canon 1190 of the Code of Canon Law.
However, the Catholic Church permits the sale of third-class relics.
Relics may not be placed upon the altar for public veneration, as that is reserved for the display of the Blessed Sacrament (host or prosphora and Eucharistic wine after consecration in the sacrament of the Eucharist).
