EVERY altar must have the relic of a saint or martyr enclosed within it, but few know how the custom arose, or what an effect the veneration accorded to relics has had on the position and material of the altar — and, indirectly, on the arrangement of the sanctuary itself.
When, during the first century, the practice of burying martyrs in the catacombs arose, the liturgy was occasionally celebrated on a portable altar. This was the first time that the altar appeared in association with the relics of martyrs. Between 269 and 275 Pope Felix I stipulated that all Masses should be said over the tombs of martyrs. From this time stone became the accepted material, and the deciding factor in the siting of early churches became the existence of the tomb of a martyr.
In 604 Pope tlregory the Great raised the sanctuary of St Peter's Basilica in Rome by seven steps over the tomb of the Apostle. Many other Roman churches followed suit, and so the practice of raising the altar several steps above the nave was introduced.
The Second Council of Nicea (787) ordered the placing of relics beneath all altars.
All this time the custom had been for the priest to say Mass facing the people. In major churches, however, by th,e end of the ninth century it was cornmon to place all reliquaries on the altar itself on important feast days. Since this practice made the actions of the celebrant a trifle obscure, to say the least, it became common, for the priest to celebrate Mass with his back to the people.
The result was that the ceremonies were moved from behind the altar, where the presidential chair normally stood, to the front, in full view of the congregation, and the altar was pushed back further towards the east wall.
In large churches a feretory or shrine was often situated immediately behind the altar, and the western face served as a reredos. Where no shrine existed altars were built against the east wall and the wall above was usually covered with sculpture.
In the centuries following, the altar was loaded with gradines, reredos, tabernacle, exposition throne, candlesticks and reliquaries, until during the sixteenth century in Europe and during the nineteenth century in this country the altar became more like a sideboard than a table.
The twentieth century saw a return to the simplicity of the altar as a table and the celebrant takes his position facing the people as he did in the first centuries of the Church.
Dr D. M. Chappell