La Stanza Gialla

The "Room of the Columns" is rectangular in plan and covered by a segmental barrel vault. One row of four columns originally ran parallel, and at short distance to, each of the long walls; only those on the north side are now preserved. This is a characteristic feature of the so-called "colonnaded oecus" – a reception room typical of the Late Republican and Early Imperial period – of which the "Room of the Columns" is the only known example in Rome. The Ionic columns, now partly restored, are made of a core in peperino stone and covered by a layer of stucco. The slightly tapered shafts rest on top of a plain stuccoed torus.

Light and air entered this chamber only through lightwells positioned at the center of the short sides: the "Room of the Columns" must have always been, therefore, located underground. It probably had the main function of reception/banquet room, used primarily during the summer.

The walls are decorated with figurative and geometric elements painted on a white background, in a sober style typical of this period. The choice of light colors and the solid white background takes full advantage of the little natural light available and gives the impression of a somewhat larger room.
The paintings on the north wall have been detached and recently repositioned after meticulous restoration: the conservators had to carefully remove a thick layer of limestone deposit that had completely obliterated the ancient surface.

The paintings, in 4th Pompeian style, represent figures and objects associated with religious rituals or idyllic representations of nature: sacred implements, garlands, candelabra, tree branches and flowers, real or fictional animals, and miniature landscapes. The repertoire includes pictures of a thyrsus – a staff decorated with ivy and vine and topped with a pine cone – that the ancients associated with Dionysiac rituals and festivals.

A few fragments of painted stucco on the vault suggest that the ceiling was entirely decorated with geometric patterns. The chromatic and stylistic similarity between the decorative motifs on the walls and the ceiling show that Roman architects conceived the two as complementary. Floors, on the other hand, followed independent decorative schemes.

The floor in the "Room of the Columns" is almost entirely preserved. It is composed of pieces of stone (palombino and slate) or colored marble (Giallo Antico, alabaster, Africano, serpentine, Breccia di Aleppo, and others) embedded in a layer of lime mortar mixed with terracotta powder (cocciopesto). Inside this pattern of tightly arranged stone fragments, four larger slabs – two hexagonal in Palombino and two rhomboidal in different stones – stand out. Finally, a circular slab of Breccia di Aleppo – a sort of emblema or centerpiece – is placed in vicinity of the back wall and on the central axis of the room. The insertion of rare colored marble in pavements to increase their visual impact is also well attested in the mosaic floors of Pompeian houses.