Lower terrace

The lower terrace is a long rectangle (100 x 40 m) supported by a wall with massive buttresses, the cladding of which is in opus mixtum of brick latticework.

In the centre of the terrace is the garden, one of the focal points of the entire complex, surrounded by a peristyle and onto which face many rooms. At each end of the garden were two large semicircular basins with fountains and steps at the corners, entirely covered with slabs of white marble; both were flanked by a masonry base which perhaps supported a basin.^[5]

To the west of the garden is the main building, the most imposing of the whole complex, and the one that has yielded the greatest number of finds of sumptuous stucco and marble decorations. The triclinium (summer dining room) (13 x 9 m) is in the centre, accessed by four doors spaced by large windows that open onto the side rooms. The entrance from the garden was framed by a pair of columns. On the back wall there is a nymphaeum consisting of three niches from which water poured into the pool below. The niches were framed by marble shelves, decorated with dolphins and tritons, on which were small columns supporting the decorated architrave. Above there was a mosaic band composed of glass-paste tesserae reflecting the sun's rays which, hitting the pool of water, created a play of light and colours on the surrounding walls in marble and stucco gold. The nymphaeum had an arch which created harmony and grace to the whole structure. The floor was decorated in colourful opus sectile, i.e. rectangular slabs of marble bordered by strips in giallo antico (antique yellow).

On both sides of the triclinium is a series of rooms of identical shape, size and function: first a large rectangular atrium (18 x 7.2 m), framed by a double pair of columns. The rooms at the back were intended for prestigious guests. These had two distinct entrances, one on each corner, placed on either side of the large window that overlooked the atrium-vestibule; the roof was a high barrel vault on massive brick pillars, while the floors were in opus sectile. The decoration of the walls (coloured marble and stucco) and the vault (frescoes) was extremely precious of which a large number of fragments have been found.^[6]

The garden was surrounded on three sides (East-West-South) by arched and vaulted porticoes: to the South (long side towards the road) and to the East (one of the two short sides) columns are composed of brick half-columns covered with stucco. On the west side, however, the pillars were replaced by nine fluted columns and an architrave in cipollino marble on Ionic bases of white marble with wider intercolumns in the centre. The south portico constitutes the access corridor to the public wing, located in the western part of the terrace; the vault of this portico was decorated with continuous frescoes on a dark background with red ribs and a central oculus placed on the vertex, while the floor was covered in slabs of white marble. Evidence of this frescoed vault was the discovery of a substantial central portion of a clipeus depicting a Winged Victory, the deity who announced the outcome of battles, with sword and gold disc. To the south, along the road, the portico had large windows with a view over the magnificent landscape.

On the north side of the garden is the wall supporting the upper terrace, decorated by a succession of niches covered in marble from which water flowed. Shortly after the construction, however, these niches-fountains were walled up, probably due to their instability.

At the south-east corner an annex protruding towards the road is the vestibulum or main entrance of the villa from the via Praenestina below from which a staircase lead to the terrace.

The porticoes employed an architectural novelty, the flat arch, which allowed straight architraves to be used without expensive monolithic marble lintels.^[7]

Upper Terrace

A geophysical survey identified underlying structures of the upper terrace which was shown to be the private residential part of the villa, including thermal baths and an elliptical structure, probably a vivarium, a large tank for breeding fish.

Water supply

The Villa was fed by two large cisterns located at a higher level. One, on the north-east hill, consists of two long rectangular rooms with barrel vaults, connected by open passages in the central wall. The second cistern, the remains of which are incorporated in houses, stood to the west, closer to the upper terrace and was used to feed the fountains inside the Triclinium. All the outgoing water flowed outside through a tunnel that flows under a buttress of the terrace.

Identification

At the end of the 19th century a series of fistula acquaria (lead water pipes) were found near the villa bearing the imperial title and the name of the procurator, Hebrus, the same as for Trajan's villa at Centumcellae (today's Civitavecchia). This allowed the complex to be attributed with certainty to Trajan and also to fix its date. The following text is on the first series of fistulae:^[12]

Imp(eratoris) Nervae Traiani Caesar(is) Aug(usti) Germanic(i) sub cura Hebri lib(erti) proc(uratoris): (Of the Emperor Nerva Trajan Caesar Augustus Germanicus, under the care of Hebrus, freedman and procurator)

This group can be dated between 97 AD and 99 AD because the epithet "Germanicus" was acquired after his victory in the wars against the Germans. On the second series is:^[13]

Imp(eratoris) Caesaris Nervae Traiani Optimi Aug(usti) Germanic(i) Dacici: (Of the Emperor Caesar Nerva Trajan Optimus Augustus Germanicus Dacicus)

This group is dated 114-5 AD as the attribute "Dacicus" indicates his victory in the two Dacian wars in 106 AD, but the attribute "Parthicus" is not present, which he received only in 116 AD after victory over the Parthians.

In support of these dates are other archaeological data, such as the building technique in opus mixtum, typical of the Trajanic age.