This simple yet elegant building – often overlooked by visitors because it is somewhat out of the way – is south of the Imperial Palace and near the Firemen’s Headquarters (Caserma dei Vigili).
It is approached from east via a corridor passing behind the stepped nymphaeum of the Imperial Palace. This corridor is a long cryptoporticus that still retains its white mosaic floor, decorated with squares of colored tesserae in the shades of green and yellow – reminiscent of another mosaic found at the Golden Square (Piazza d’Oro).
From the cryptoporticus, a few steps lead down into a large rectangular portico. Instead of columns, it had fluted piers supporting a Doric frieze, hence its name; those piers were re-erected and restored in the 1950s.
A fragment of this same Doric frieze can also be seen in Tivoli at Piazza Palatina, where it was incorporated into the façade of the Palazzo Boschi-Del Re as a decorative element (see bibliography). The portico’s central area was also paved in opus sectile, so it was supposed to have a roof, but this is unlikely given the portico’s vast dimensions.
Opening off the west side of the portico, in a central axial position, is a large rectangular hall (PD7). Also paved in opus sectile, it still retains some original cipollino marble slabs still in situ.
Its walls were once entirely clad in precious marbles; today, only the holes for mounting clamps remain, along with large rectangular recesses designed to hold reliefs, which have, of course, been lost.
The hall is flanked by four symmetrical, elongate d rectangular rooms; some of these are currently used to store marble fragments recovered from the excavations.
Hall PD7 opens onto a large garden that served as the scenic backdrop for the whole complex; at its far end, it had an apse with niches and a central base for a statue. A portico (PD10) ran around the perimeter, paved with white mosaic decorated with fragments of colored marble – a pattern imitating the Republican-era mosaic seen in the portico of the nearby Imperial Palace.
This space was once known as the «Throne Room« due to the central pedestal, but this theory is untenable because the area was in open air.
The function of Throne room is more likely attributable to the Hall of the Philosophers, which was far larger and more monumental, and richly decorated with red porphyry – a stone symbolizing imperial power.
The Building with Doric Pillars acted as a connecting link, providing access to nearby buildings: the Golden Square (Piazza d’Oro), the Imperial Palace, and the Winter Palace (Edificio con Peschiera).
It may also have served as a space to display a collection of sculptures or precious objects. Unfortunately, antiquarian excavation records offer no clues in this regard.
BIBLIOGRAPHY:
Marina De Franceschini, «I marmi architettonici di Villa Adriana "murati per le case di Tivoli"» in Marmora 15, 2019, pp. 123-154.
Marina De Franceschini, Villa Adriana. Mosaici, pavimenti, edifici. Rome 1991, pp. 134–139 and 417–421.