APRON STAGE, in theatre design, the portion of the stage projecting into the auditorium. In England, the Elizabethan platform stage developed during the Restoration period into the wide "apron" extending from the proscenium arch. The apron itself was level, whilst the stage behind it generally sloped slightly upwards. This form of stage was unknown on the continent of Europe in the i 7th century, and was peculiar to the English theatre. Early in the 19th century, when the curtain came into statue of a deity in a temple. From this original derivation the use of the form spread to other types of building, especially to the basilica as seen in the Imperial basilica in the palace of Domitian on the Palatine Hill (see illustration under BASILICA) . The apse form thus used was, from the beginning, universally adopted by the early Christians as the climax of their churches. In the basil icas of the time of Constantine, in the western part of the empire the apse always faced the west so that the rising sun might shine directly into the church. This was the orientation of the apse in old St. Peter's at Rome. During the 6th and 7th centuries, how ever, the usage in this matter gradually changed, so that churches in the west, like those in the east, had their apses toward the east and this has remained the custom ever since. The apse of the early Christian basilica was the place in which the clergy sat, the altar being situated between them and the rest of the church. This arrangement is still preserved in the apse of the cathedral at Torcello and in that of the church at Parenzo in Istria. In both cases there are semicircular benches of marble following the line of the apse and arranged in several stages, one above the other like the seats of an ancient theatre. In the centre, on the axis, was the bishop's throne, raised above the clergy benches and approached by a flight of steps. With the development of the choir as the place for the clergy seats, the old use of the apse naturally dis appeared and the altar was pushed back into the apse until, in many Renaissance churches, it is against the back wall.
The apse was the place for the richest decoration in the church structure. It was sheathed with marble, frequently in elaborate patterns of light and dark, and the vault surface was covered with a glass mosaic in which some embodiment of the Godhead was the chief feature.
At the end of the 6th century, liturgical changes rendered neces sary the addition of other apses besides the main choir apse. These were frequently placed at the end of the side aisles but occasionally, when there was a transept, at the ends of the tran sept (as in the basilica at Bethlehem and in many examples of Coptic churches).
By the time Romanesque design was developing in western Europe, apse chapels had also been added to the church plan. This at once gave a great opportunity for enriching exterior design, till then severely simple, and led eventually to the development of that complex and magnificent combination of main apse and apse chapels known as the chevet (q.v.). In Italy, however, where chapels were usually confined to other portions of the church, the apse remained simple in form and gained its richness from the use of wall arcading, cornices and buttresses.
The apse, because of its shape, enclosed on one side and open on the other, gives great dignity to any object, such as an altar or statue, placed in its centre. It is, therefore, an admirable form with which to terminate any vista or to end any large hall, and it is so used in much modern secular work. (T. F. H.)