Vomitorium in the context of Amphitheatre of Pompeii

In theatre, a thrust stage (a platform stage or open stage) is one that extends into the audience on three sides and is connected to the backstage area by its upstage end. A thrust has the benefit of greater intimacy between performers and the audience than a proscenium, while retaining the utility of a backstage area. This is in contrast to a theatre in the round, which is exposed on all sides to the audience, is without a backstage, and relies entirely on entrances in the auditorium or from under the stage. Entrances onto a thrust are most readily made from backstage, although some theatres provide for performers to enter through the audience using vomitory entrances. As with an arena, the audience in a thrust stage theatre may view the stage from three or more sides. Because the audience can view the performance from a variety of perspectives, it is usual for the blocking, props and scenery to receive thorough consideration to ensure that no perspective is blocked from view. A high-backed chair, for instance, when placed stage right, could create a blind spot in the stage left action.

The Tours amphitheatre (also known as the Caesarodunum amphitheatre) is a Roman amphitheatre located in the historic city centre of Tours, France, immediately behind the well known Tours cathedral. It was built in the 1st century when the city was called Caesarodunum. It was built atop a small hill on the outskirts of the ancient urban area, making it safe from floods, convenient for crowds and visitors, and demonstrating the power of the city from a distance. The structure was an enormous, elliptical structure approximately 122 metres by 94 metres. According to its design it is classified as a "primitive" amphitheatre. Unlike the famous Colosseum that was made mostly of masonry and built above-ground, the Tours amphitheatre was made mostly of earth and created by moving soil and rock into a bowl shape. Spectators likely sat directly on the grassy slopes, while the masonry was primarily used for the vomitoria and retaining walls.

When it was expanded in the 2nd century (to 156 m X 134 m), it became one of the largest structures (among the top ten) in the Roman Empire. It is not clear why the amphitheatre was expanded given the population and slow growth of the city at the time. About a century later, this expanded amphitheatre was transformed into a fortress, with an addition of a rampart-style wall, typical during the decline of Roman Empire. It gradually fell into ruin during the Middle Ages and canonical houses were built upon it and gradually concealed it. The vomitoria were at some point transformed into cellars.