Altar (Catholic Church)

Based on Wikipedia: Altar (Catholic Church)

The Stone That Holds the Body of Christ

Somewhere beneath almost every Catholic altar in the world, sealed inside a small cavity, lie the bones of the dead.

This practice—entombing the remains of saints and martyrs inside the very surface upon which the Eucharist is celebrated—stretches back nearly two thousand years. It connects every parish church to the catacombs of Rome, where persecuted Christians once gathered in underground burial chambers to break bread over the tombs of their murdered companions. The altar, in other words, is not merely furniture. It is a memorial stone, a sacrificial table, and a reliquary all at once.

To understand the Catholic altar is to understand something essential about how the Church thinks about space, time, and the presence of the holy in ordinary matter.

From Kitchen Table to Sacred Object

The earliest Christian altars looked nothing like the ornate marble structures you might see in a Gothic cathedral today. They were ordinary wooden tables—the same kind you would use for dinner. This makes sense when you remember that the central Christian ritual emerged from an actual meal. Jesus and his disciples gathered around a table at Passover, and he told them to repeat what he did with bread and wine "in remembrance of me."

For the first few centuries, Christians simply borrowed household furniture. One ancient wooden table, tradition claims, was used by the apostle Peter himself. It survives in the Lateran Basilica in Rome—if the tradition is true, it may be the oldest surviving piece of Christian liturgical equipment in the world. Fragments of another ancient wooden altar exist in the church of Santa Pudenziana, also in Rome.

We know these early altars were made of wood because fourth-century writers complain about what happened to them. Optatus of Mileve, a bishop in what is now Algeria, wrote indignantly that the Donatists—a schismatic Christian group—had broken up Catholic church altars and burned them for firewood. Augustine of Hippo recorded that a bishop named Maximianus was beaten with pieces of a wooden altar under which he had tried to hide during an attack.

Wood, however, presents problems. It rots. It burns. It splinters under violence.

Stone endures.

Why Stone Became Standard

Gregory of Nyssa, a fourth-century theologian writing in what is now Turkey, mentioned the consecration of a stone altar around 380 AD. By 517, a church council in Epaune (in modern France) formally decreed that altars intended for consecration should be made of stone. The rule stuck.

The reasons were practical and symbolic. Stone resists decay and corrosion better than wood or base metals. Gold and silver would work even better—and wealthy donors did occasionally give precious metal altars to important churches—but few congregations could afford such extravagance. An empress named Pulcheria presented a golden altar to Constantinople's great basilica in the early fifth century. But for ordinary parishes, local stone was the affordable option that would last for centuries.

The symbolism ran deeper. Ancient Fathers of the Church wrote that the stone altar was "made holy when it receives the body of Christ." There is something fitting about the permanence of stone receiving what Catholics believe to be the eternal made present in time. The altar becomes, in the words of one ancient text, "an object of awe: by nature it is stone, but it is made holy."

Modern Catholic regulations maintain this preference while allowing some flexibility. The General Instruction of the Roman Missal specifies that the top surface of a fixed altar—called the "table"—should be natural stone. The base or supports can be made of other dignified materials. Episcopal conferences (the regional bodies of bishops) may authorize different materials like wood for the table in certain circumstances. Movable altars can be constructed of "any noble and solid material suited to liturgical use."

The Eastern Catholic Churches, which maintain their own liturgical traditions while remaining in communion with Rome, permit stone, wood, or metal.

The Bones Below

Here is where the story becomes macabre by modern sensibilities—and profoundly meaningful by ancient ones.

During the Roman persecutions, Christians were executed for refusing to worship the emperor or the traditional gods. Their fellow believers considered these martyrs to be especially close to Christ, who had himself been executed by Roman authority. The bodies of martyrs were precious. Christians preserved them, venerated them, and gathered to pray at their graves.

In the underground cemetery complexes called catacombs—tunnels carved into the soft volcanic rock called tufa beneath Roman suburbs—Christians would hollow out niches in the walls to create space for worship. They would place a stone slab over the grave or sarcophagus of a martyr and celebrate the Eucharist on that surface. The tomb became the table.

This practice is probably ancient. The Liber Pontificalis, a medieval collection of papal biographies, attributes the custom to Pope Felix I in the 270s, though modern historians suspect it predates him. What matters is the theological intuition behind it: that the community should gather for its most sacred meal in the presence of those who had given everything for the faith. The living and the dead, united in Christ, sharing the same sacred space.

When Christianity became legal in 313 AD and Christians began building above-ground churches, they often constructed them directly over the burial places of martyrs. The great basilica of Saint Peter in Rome sits atop what Catholics believe to be Peter's grave. The altar stands above the tomb.

But not every church could be built over a martyr's grave. So the practice evolved: if you cannot bring the church to the relics, bring the relics to the church. Bones, or fragments of bones, were removed from the graves of martyrs and placed inside new altars. A small cavity called the sepulchrum—Latin for "tomb"—was carved into the altar stone. The relics were sealed inside, sometimes with grains of incense and a parchment document attesting to their authenticity.

For centuries, this was mandatory. Every consecrated altar had to contain relics, and at least two of the saints represented had to be martyrs. The rule was relaxed somewhat in 1906, when the Vatican's Congregation of Rites decided that relics from two canonized saints were sufficient, only one of whom needed to be a martyr.

The Problem of Authenticity

There is an obvious difficulty with a practice that demands fragments of ancient bones for every altar in Christendom. How do you know the bones are genuine?

The medieval relic trade was, to put it charitably, enthusiastic. Multiple churches claimed to possess the same saint's head. Entrepreneurs manufactured fraudulent relics for profit. The Protestant reformers mocked the whole enterprise: John Calvin quipped that if you gathered all the fragments of the True Cross venerated across Europe, you would have enough wood to build a ship.

Modern Catholic regulations address this with characteristic caution. The General Instruction of the Roman Missal directs that relics must be verified as authentic. The Caeremoniale Episcoporum—the book governing ceremonial practices for bishops—adds that the relics must be "of a size sufficient for them to be recognized as parts of human bodies." No microscopic splinters or single teeth allowed. "It is better for an altar to be dedicated without relics," the text declares, "than to have relics of doubtful authenticity placed beneath it."

The relics are no longer required to be martyrs' bones. The remains of any canonized saint will do. And in practice, many modern altars are dedicated without relics at all, particularly in mission territories or newly established parishes where authenticated relics are difficult to obtain.

But where the practice continues, it maintains that ancient link between the altar and the grave, between the Eucharist and the witness of those who died rather than deny their faith.

Facing East, Facing the People

If you have attended Catholic Mass in different eras or different churches, you may have noticed that the priest sometimes stands behind the altar facing the congregation, and sometimes stands in front of it with his back to the people. This is not a matter of personal preference or architectural accident. It reflects centuries of theological debate about the meaning of the Eucharist and the direction of Christian prayer.

Early Christians prayed facing east. This is well attested by writers like Clement of Alexandria (around 150-215 AD), Tertullian (around 160-220 AD), and Origen (around 185-253 AD). The east was the direction of the rising sun, a symbol of Christ the "light of the world" and of his expected return in glory. Churches were typically built on an east-west axis to facilitate this orientation.

In the earliest Roman churches, the altar stood at the western end of the building. The priest stood on the west side of the altar, facing east—which meant he was also facing the congregation and the main doors, which opened toward the east. If you visit the original basilica of Saint Peter (now beneath the Renaissance structure) or the ancient basilica of Saint Paul Outside the Walls, this is how things were arranged.

Eastern churches did it differently. They placed the altar at the eastern end, and the priest stood on its western side, facing east—which now meant his back was to the congregation. This arrangement eventually became dominant in Western Europe as well, adopted in Rome sometime in the eighth or ninth century.

The Second Vatican Council in the 1960s encouraged the construction of freestanding altars that would allow the priest to face the people. This was presented not as an innovation but as a recovery of ancient practice. Most Catholic churches built or renovated since the 1960s have their main altar arranged this way. But the older orientation was never forbidden, and in recent decades some parishes have returned to celebrating Mass with the priest and people facing the same direction—toward the liturgical east, whether or not that corresponds to the compass.

The Architecture of Encounter

When Christians gained the legal right to build public places of worship in the fourth century, they faced a design problem. Pagan temples were not useful models—they were designed as houses for cult statues, not as gathering spaces for large assemblies. The people stayed outside while priests performed rituals within.

Christianity needed buildings that could hold hundreds or thousands of people for weekly gatherings. The model they borrowed was the Roman basilica: a civic building type used for law courts, markets, and public meetings. Basilicas were spacious rectangular halls with the interior divided by rows of columns into a central nave and side aisles. At one end, a raised platform—often in a semicircular apse—held seats for magistrates.

In Christian adaptation, the apse became the sanctuary, holding the bishop's throne (called the cathedra, hence "cathedral") and seats for assisting clergy. The faithful occupied the nave and aisles. Between clergy and people stood the altar.

This fundamental arrangement has persisted through two millennia of architectural evolution. Gothic cathedrals, Baroque churches, modernist worship spaces—all of them maintain some version of this spatial grammar: a designated area set apart for the altar, elevated above the rest of the building, marked as sacred.

The regulations are specific. The altar should be located in the sanctuary and "set apart from the rest of the church in some way." The sanctuary itself is typically elevated above the nave floor. It may be demarcated by altar rails (also called communion rails), though these have become less common since the mid-twentieth century. Within the sanctuary, the altar often stands on its own raised platform—called the predella—set off by one or more steps.

Why Odd Numbers of Steps

Here is a detail that reveals how seriously pre-modern liturgists took their craft: the number of steps leading up to an altar was always odd.

The main altar of a church typically had three steps. Side altars had one. The papal altar in Saint Peter's Basilica has seven. Why odd? Because it was considered proper to begin ascending with the right foot—the "right" foot in both senses, the correct and auspicious one. If you start with your right foot and the number of steps is odd, you will also step onto the altar platform with your right foot. An even number of steps would land you on your left.

This concern predates Christianity. The Roman architect Vitruvius, writing in the first century BC, noted that temple steps followed the same rule for the same reason. The novel Satyricon, attributed to the courtier Petronius in the age of Nero, mentions the custom of dextro pede—right foot first.

Medieval and early modern liturgists developed elaborate regulations about altar steps: their height, the breadth of each tread, the materials used, the carpets or rugs that should cover them (removed from Holy Thursday until Easter), and the colors and designs appropriate for each season. Most of these detailed prescriptions are no longer enforced, but they witness to an era when every physical detail of worship was thought to carry meaning.

Canopies and Curtains

In many historic churches, the altar stands beneath a canopy supported by four columns. This structure is called a ciborium (or sometimes a baldachin, from the Italian word for the fabric of Baghdad, once prized for such hangings). The most famous example is Gian Lorenzo Bernini's massive bronze baldachin in Saint Peter's Basilica, completed in 1634, rising nearly a hundred feet above the papal altar.

Early examples survive in Ravenna and Rome: four columns topped by a pyramidal or gabled roof. Some of these ancient ciboria have rods between the columns, indicating that curtains once hung there. These curtains could be closed at certain moments of the liturgy, hiding the altar from the congregation's view.

This practice of veiling the altar during parts of the Mass strikes modern sensibilities as strange. Why hide the central action? But it made sense in a theology that emphasized the fearsome mystery of what was occurring on the altar. The moment of consecration—when Catholics believe bread and wine become the body and blood of Christ—was too sacred for casual viewing. The curtains created a visual barrier between the ordinary world and the holy of holies.

Other architectural features eventually served the same function. In Eastern churches, the iconostasis—a wall of icons—screens the altar from the nave. In medieval Western churches, rood screens and pulpita (stone choir screens) blocked the congregation's view. By the time these structures became common, the curtains were superfluous; the people could barely see the altar anyway.

The Reserved Sacrament

In the early centuries, before the collapse of Roman order exposed church treasures to plunder, the consecrated bread of the Eucharist was often kept suspended above the altar in a container shaped like a dove. This dove, made of gold or silver, might be enclosed in a silver tower, hanging by fine chains from the ciborium above.

The bread reserved in this way—called the "reserved sacrament"—served practical purposes. It could be taken to the sick or dying who could not attend Mass. It also became an object of devotion in itself, as Catholics came to believe that Christ remained truly present in the consecrated elements as long as they retained the appearance of bread.

The practice of reserving the Eucharist continues today, though typically in a tabernacle (a locked container, often quite ornate) rather than a suspended dove. The tabernacle may be located on the main altar, on a side altar, or in a separate chapel. Its presence is signaled by a sanctuary lamp—a candle that burns continuously as long as the sacrament is reserved within.

What Goes on the Altar

The Roman Missal of Pope Pius V, issued in 1570 and made obligatory throughout most of the Latin Church, established a principle that remains in force: during Mass, only items actually used in the celebration should be placed on the altar.

This sounds obvious, but it was a corrective. Over the centuries, altars had become cluttered with devotional objects, votive offerings, flowers, relics in elaborate cases, and decorative items that had nothing to do with the Mass being celebrated. The reform insisted on simplicity: a cross in the middle (or positioned nearby where it is clearly visible), at least two candlesticks with lit candles, and the items needed for the liturgical action itself.

The altar is to be covered with at least one white cloth during Mass. Before the 1969 reforms, regulations required three white cloths, with the topmost long enough to reach the ground at both ends. Nineteenth-century rules specified that these cloths must be linen or hemp—not cotton, silk, or any other material, even if more beautiful. Beneath the altar cloths, a waxed cloth called the chrismale protected the cloths from moisture.

When the altar is not in use, a protective cover—called a vesperale or stragulum—may be placed over the cloths to prevent staining. This practical item, made of cloth, baize, or velvet, hangs down slightly on all sides like a tablecloth protecting furniture between meals.

The Niche of the Palliums

In some ancient churches where the altar is built over a saint's tomb, a niche below the altar allows the faithful to see and touch the holy place. The most famous example is the Niche of the Palliums in Saint Peter's Basilica. The pallium is a woolen vestment worn by archbishops as a sign of their authority, and these garments are stored briefly in this niche before being presented to new archbishops—placing them in contact with what is believed to be Peter's grave.

Descending steps now lead to this niche, because the floor of the current basilica is considerably higher than the floor of the original Constantinian church. You go down to reach the oldest and holiest level.

Similar semicircular hollow areas, called confessiones, exist in other Roman churches—including the Lateran Basilica and Santa Maria Maggiore—even when no saint is buried directly beneath. The architectural form persisted after the original reason for it no longer applied. The shape became traditional, a memory in stone of the original union between altar and tomb.

The Altar Today

Walk into almost any Catholic church today and you will find the altar at the focal point of the building. The General Instruction of the Roman Missal says it should be "the focus of attention in the church." The priest reverences it with a kiss at the beginning of Mass before doing anything else—a gesture of respect for the table that holds the Eucharist and, in many cases, for the saints whose bones rest within.

The altar you see may be a simple wooden table in a modern chapel or an ornate marble structure in a centuries-old cathedral. It may contain authenticated relics of martyrs or no relics at all. The priest may stand behind it facing you, or in front of it facing the same direction you face. The specific arrangements vary with era, culture, and local custom.

But the essential meaning persists. This is the table where Christians believe that bread and wine become the body and blood of Christ, that heaven touches earth, that the sacrifice of Calvary is made present again. It stands above the bones of the dead who witnessed to their faith unto death. It is, as one ancient text put it, "by nature stone, but made holy when it receives the body of Christ."

The altar is where the living and the dead, the visible and the invisible, the ordinary and the sacred, meet.