Altar Ledge
From the Catholic Encyclopedia
Originally the altar was made in the shape of an ordinary table, on which the crucifix and candlesticks were placed. By degrees, behind the altar a step was introduced, raised slightly above it, for candlesticks, flowers, reliquaries, and other ornaments. This step was called the altar-ledge. Later the tabernacle was added as a stationary appends of the altar and at its sides and behind it other steps were placed. They are sometimes called degrees or gradini. The front of these steps was sometimes beautifully painted and decorated. The gradini of Brunelleschi's church of Santo Spirito, Florence, display beautiful miniature groups of subjects from the Passion of Christ.
A.J. SCHULTE