The consecration of a Catholic church is a very solemn and impressive ceremony, with rites that devote the edifice exclusively to sacred use. The various parts of the traditional ceremonies of consecration are of very ancient date, and are substantially the same today as they were many centuries ago.
As formally decreed by the Council of Trent, Holy Mass is not to be celebrated in any place except a consecrated or blessed church, which is why the Church wants that cathedrals and parish churches be solemnly consecrated, and that smaller churches be blessed. The consecration of a church is reserved to a bishop, by which the church is dedicated to the service of God, thereby raising it perpetually to a higher order, removing it from the malign influence of Satan, and rendering it a place in which favors are more graciously granted by God (Pontificale Romanum).
As part of the consecration of a church, at least one fixed altar must be consecrated. According to the Catholic Encylopedia (1913), before the time of Constantine, the consecration of churches was a private matter due to persecutions. However, after Constantine’s conversion, it became a public rite: “After these things a spectacle earnestly prayed for and much desired by us all appeared, viz. the solemnization of the festival of the dedication of churches throughout every city, and the consecration of newly-built oratories” (Eusebius of Cæsarea, Church History X).
Placing relics of saints inside an altar is a practice that finds its roots in the Bible.
A little-known detail in Catholic Churches is the presence of saint relics inside the primary altar reserved for the sacrifice of the Mass. These relics are generally encased inside an altar stone, though sometimes they can be visibly displayed in special reliquaries.
It is an ancient custom that the Church retains, as specified by the General Instruction of the Roman Missal, “The practice of the deposition of relics of Saints, even those not Martyrs, under the altar to be dedicated is fittingly retained. However, care should be taken to ensure the authenticity of such relics.”
(Sources: aleteia.org; TraditionalCatholicism.com)
Read more in the “Why Do We Do That?” series from Deacon Mike Fritz.
Our altar at Holy Trinity contains the relics of Saint Martyrs from Florence, Italy. This is the “Testimony of Consecration” that is affixed to the underside of our altar. It ensures the authenticity of our relics. Of course, it’s in Latin, the official language of the Holy See and the Roman Rite of the Catholic Church: