The structure of the trilobed room, which occupies one quarter of the surface area of the Loupian apartments, is typical of upper-class dwellings in the Late Antique period, and was widely adopted in the Empire's western provinces. It was used for banqueting and for receiving guests. The apses may have held semi-circular banqueting couches, known as stibadium or sigmae, which became popular starting in the late 3rd century CE. Its use is attested to under the Early Empire, in a garden setting, or combined with fountains for summer dining.
The stibadium was a wooden piece of furniture, consisting of one or more elements, measuring at least 3 metres in diameter. The length of the reclining area varied, but it would only have been comfortable when it was 1.4 metres or longer. Covers and cushions for four to eight persons, depending on the size of the couch, were added. A circular or U-shaped table held tableware and food. Seating followed strict rules; the host took his place at one end of the couch, and the guest of honour occupied the other. Other guests were seated between them in decreasing order of importance. The meal was taken in the apses, while the central room was used for serving and for the entertainment. At the Loupian villa, the theme of the room's mosaic is reminiscent of the open-air origins of the stibadium, with a decor consisting of porticos and a plant-covered pergola.
