Relics in Altars

St. Thomas Chapel in St. Peter's Basilica
is so named b/c of the altar piece rendition of
St. Thomas' famous inspection of Jesus' wounds.
The relics below the altar are of St. Boniface,
so it is also called St. Boniface Chapel.

A question was posed to me today: Do all altars have to have relics in them?

My initial response was that while it is preferred to have a relic in the altar, it is not required, but I did a little research to make sure.

Here is what I found:

First, let's consider why we put relics under the altar to begin with:

Dedication of a Church or Altar (DCA) IV, 5. All the dignity of the altar rests on its being the Lord’s table. Thus the martyr’s body does not bring honor to the altar; rather the altar does honor to the martyr’s tomb. For it is altogether proper to erect altars over the burial place of martyrs and other saints or to deposit their relics beneath altars as a mark of respect and as a symbol of the truth that the sacrifice of the members has its source in the sacrifice of the Head. Thus ‘the triumphant victims come to their rest in the place where Christ is victim: he, however, who suffered for all is on the altar; they who have been redeemed by his sufferings are beneath the altar.’ This arrangement would seem to recall in a certain manner the spiritual vision of the Apostle John in the Book of Revelation: ‘I saw underneath the altar the souls of all the people who have been killed on account of the word of God, for witnessing to it.’ His meaning is that although all the saints are rightly called Christ’s witnesses, the witness of blood has a special significance that only the relics of the martyrs beneath the altar express in its entirety.

[As Jesus' sacrifice is made present on top of the altar, He is made present above those who have died for Him. He is the head and they are the body. This also foreshadows the Resurrection of the Body, when at the end of time, God will bring our mortal bodies back from decomposition and reunite our souls to them in a glorified manner, and those who are going to Heaven will rise together as one Body with Jesus as our head.]

Revelation 6:9: “I saw underneath the altar the souls of all people who had been killed on account of the word of God, for witnessing to it.”

[Revelation is St. John’s record of the vision of Heaven that he was given. Our tradition of building altars above relics is tied up with this vision.]

Now to our question: Do all altars have to have relics?

Canon Law 1237 §2: The ancient tradition of placing relics of martyrs or other saints under a fixed altar is to be preserved, according to the norms given in the liturgical books.

[While this says that the tradition is to be preserved, it doesn't give any specifics about the tradition, nor what the liturgical books say.]

GIRM 302: The practice of placing relics of Saints, even those not Martyrs, under the altar to be dedicated is fittingly retained. Care should be taken, however, to ensure the authenticity of such relics.

[This is basically what Canon Law states, but it also gives the stipulation that the relic needs to be authentic. We don't want just a random person's bone(s) below our altars. The altar honors the saint's bones.]

DCA II, 5. The tradition in the Roman liturgy of placing relics of martyrs or other saints beneath the altar should be preserved, if possible. But the following should be noted:

a) Such relics should be of a size sufficient for them to be recognized as parts of human bodies. Hence excessively small relics of one or more saints must not be placed beneath the altar.

b) The greatest care must be taken to determine whether the relics in question are authentic. It is better for an altar to be dedicated without relics than to have relics of doubtful authenticity placed beneath it.

c) A reliquary must not be placed upon the altar or set into the table of the altar; it must be placed beneath the table of the altar, as the design of the altar permits.

[So, the tradition “should be preserved, if possible.” That answers the original question: not every altar must have a relic. It also specifies more about the relic requirements. They should be sizable, not just those little bone chips you normally see. Note: there is a distinction between “shoulds” and “musts” in Church documents, but “shoulds” are still to be followed, if possible. The relic must not be on top, but must be below the table of the altar. This fits more with Rev. 6:9 - the souls are underneath the altar.]

DCA II, 14. When relics of a martyr are not available, relics of another saint may be deposited in the altar.

[This also fits with Rev. 6:9. The souls who were underneath the altar “had been killed no account of the word of God, for witnessing to it.” They were martyrs. “Martyr” means witness. It is then fitting that we prefer the relics of martyrs to be underneath our altars.]

DCA VI, 3. [I]t is not permissible to place the relics of saints in the base of a movable altar.

[This also sheds light on our initial question. Moveable altars cannot have relics, so it is necessary that not all altars will have relics, though it is preferred that fixed altars do, indeed, have relics.]

To clarify this point, lets go back to Canon Law:

Canon 1235: An altar . . . is called fixed if it is so constructed that it adheres to the floor and thus cannot be moved; it is called moveable if it can be removed.

[This begs the question as to how much effort is necessary to remove an altar for it to be considered fixed and not moveable. If a wood altar is screwed into the floor, I would imagine that it would be considered fixed, but it takes little effort to move it. Whereas a heavy stone altar might not be screwed to the floor, but it would take a great effort to move it. Would the wood be considered fixed while the stone be considered moveable, even though the stone altar is really much more fixed than the wooden one? I don’t know. Perhaps they are both fixed because more than a little effort is required to move either of them.]