Proscenium

A proscenium (Ancient Greek: προσκήνιον, proskḗnion) is the virtual vertical plane of space in a theatre, usually surrounded on the top and sides by a physical proscenium arch (whether or not truly "arched") and on the bottom by the stage floor itself, which serves as the frame into which the audience observes from a more or less unified angle the events taking place upon the stage during a theatrical performance. The concept of the fourth wall of the theatre stage space that faces the audience is essentially the same.

It can be considered as a social construct which divides the actors and their stage-world from the audience which has come to witness it. But since the curtain usually comes down just behind the proscenium arch, it has a physical reality when the curtain is down, hiding the stage from view. The same plane also includes the drop, in traditional theatres of modern times, from the stage level to the "stalls" level of the audience, which was the original meaning of the proscaenium in Roman theatres, where this mini-facade was given more architectural emphasis than is the case in modern theatres. A proscenium stage is structurally different from a thrust stage or an arena stage, as explained below.

In later Hellenistic Greek theatres the proskenion (προσκήνιον) was a rather narrow raised stage where solo actors performed, while the Greek chorus and musicians remained in the "orchestra" in front and below it, and there were often further areas for performing from above and behind the proskenion, on and behind the skene. Skene is the Greek word (meaning "tent") for the tent, and later building, at the back of the stage from which actors entered, and which often supported painted scenery. In the Hellenistic period it became an increasingly large and elaborate stone structure, often with three storeys. In Greek theatre, which unlike Roman included painted scenery, the proskenion might also carry scenery.

In ancient Rome, the stage area in front of the scaenae frons (equivalent to the Greek skene) was known as the pulpitum, and the vertical front dropping from the stage to the orchestra floor, often in stone and decorated, as the proscaenium, again meaning "in front of the skene".

In the Greek and Roman theatre, no proscenium arch existed, in the modern sense, and the acting space was always fully in the view of the audience. However, Roman theatres were similar to modern proscenium theatres in the sense that the entire audience had a restricted range of views on the stage—all of which were from the front, rather than the sides or back.

The oldest surviving indoor theatre of the modern era, the Teatro Olimpico in Vicenza (1585), is sometimes incorrectly referred to as the first example of a proscenium theatre. The Teatro Olimpico was an academic reconstruction of a Roman theatre. It has a plain proscaenium at the front of the stage, dropping to the orchestra level, now usually containing "stalls" seating, but no proscenium arch.

However, the Teatro Olimpico's exact replication of the open and accessible Roman stage was the exception rather than the rule in sixteenth-century theatre design. Engravings suggest that the proscenium arch was already in use as early as 1560 at a production in Siena.

The earliest true proscenium arch to survive in a permanent theatre is the Teatro Farnese in Parma (1618), many earlier such theatres having been lost. Parma has a clearly defined "boccascena", or scene mouth, as Italians call it, more like a picture frame than an arch but serving the same purpose: to delineate the stage and separate the audience from its action.^{[citation needed]}