Father Peter paper dolls, from the 1940s, convey the superior catechesis of the Church before Vatican II. Instructions that accompany Father Peter provide insights on the significance of the altar:
The most important thing in the church is the altar, for it represents Our Lord, Jesus Christ. St. John, in the Apocalypse, said that he saw a golden altar standing before the throne of God on Which and through Whom the offerings were made to God the Father. The altar must be of stone, and in this it also represents Christ, for St Paul tells of the Israelites drinking water from the rock, and says that the rock was Christ. In the early days of the Church, Mass was said in the Catacombs, those underground burial places used by the Christians. Some of the passages were enlarged into little chapels and in these martyrs were buried and upon their tombs priests said Mass. So today every altar must be of stone and must contain within it the relics of saints.
The henchmen of Vatican II, in their zeal to modernize and Protestantize the Church, allowed tables to substitute for altars.