1 - Pavements
2 - Wall revetments
3 - Building classification
4 - Building phases and chronology of the Villa
5 - Conclusions
3. - Building classification in Hadrian's Villa

Five hundred years of treasure hunting and no stratigraphical scientific excavation produced enormous gaps in our information. We will never reach definitive and complete identifications of the buildings and their functions. Very little is left of their original decoration, and very seldom statues, mosaics or marble reliefs can be attributed to their original building. Therefore, it is very difficult to understand how a building was decorated; only pavements and wall are left, marbles and mosaics have been stolen.

Nevertheless, the survey of the type of decoration in the buildings of Hadrian's Villa pointed out to a precise hierarchy as far as decoration, architecture and location of the buildings were concerned.

The most important feature is the prevailing type of pavement in the buildings, which corresponds to the hierarchy of the buildings themselves:

  1. servant's buildings, paved with opus spicatum or coccio-pisto
  2. secondary buildings, paved with simple black and white mosaic
  3. noble buildings, paved with opus sectile and polychrome mosaic
  4. (See Plate 1 - General plan of the distribution of pavements)

To verify if this classification is consistent, it has been cross checked with other elements, to see if they followed the same hierarchy: wall revetments, latrines, fountains, waterworks and basins, gardens, winter heating plants, architecture, access roads and paths. According to the buildings where they were located, all these elements had different features, corresponding to the same rank within the general hierarchy.

Wall revetments featured only plaster and coccio-pisto in the servant's quarters. Simple frescoes and stucco were used in secondary buildings. Only in the noble buildings we see the marble wall revetment, often reaching up to the ceiling, together with frescoes, mosaics, stucco and 'tartari' (pseudo grotto imitating stalactites). (See Plate 2 - General map of wall revetments)

Latrines were 'multi seater' in the servant's quarters and in the secondary buildings, while the noble buildings had only 'single' one-seater latrines, with precious marble decoration. (See Plate 3 - General map of latrines)

Gardens, fountains, waterworks did not exist in the servant's quarters nor in the secondary buildings. The noble buildings instead had several beautiful 'secret gardens' surrounded by porches, such as the PECILE (n. 16), the ACCADEMIA (n. 30) and PIAZZA D'ORO (n. 15). The noble buildings were surrounded by vast 'open gardens', which embellished the enormous artificial esplanades of Hadrian's Villa: the LOWER TERRACE OF THE LIBRARIES (n. 5), the ESPLANADE (n. 29a) going from ROCCABRUNA (n. 29) to the ACCADEMIA (n. 30), the great terrace which started from the PRAETORIUM PAVILLION (n. 27) and reached the substructures of the ACCADEMIA (n. 30); and also the TERRACE OF TEMPE (n. 4), and the esplanade which ran from the TEMPE PAVILLION (n. 6) to PIAZZA D'ORO (n. 15). (See Plate 4 - General map of gardens, and Plate 5 - plan of waterworks)

Winter heating plants are seen only in noble buildings: in the CASINO WITH SEMICIRCULAR ARCADES (n. 20), in the WINTER PALACE (n. 22), in the GREEK LIBRARY (n. 10) and possibly in the ACCADEMIA (n. 30). (See Plate 6 - Map of heating plants)

Type of architecture: the servant's quarters were located inside the substructures, and were similar to soldier's barracks. Secondary buildings featured a very simple architecture, with squared buildings located in secluded and often hidden areas. The architecture of the noble buildings was completely different, monumental and spectacular: curved lines were dominating, there was no rigid symmetry or axiality. Perspective was not conventional or rigid, everything was conceived to be unexpected and surprising. The highlight of creativity.

Access paths and roads. The servant's quarters had a series of subterranean and separated access roads. Secondary buildings instead had open-air access paths, which were linked to many service passageways, such as the one going from the PHILOSOPHER'S HALL (n. 17) to the GARDEN STADIUM (n. 21). Noble buildings had monumental main access roads, leading to the NINFEO FEDE (n. 3) and the PECILE (n. 16), or to the VESTIBULUM (n. 25): They were strictly patrolled and surveilled. Inside the Villa, security was also very tight: every building had several checkpoints and 'filters', so that one could not go unnoticed from a building to the other. Retaining wall were built and meant as walls surrounding and defending a real town. (See Plate 7 - Map of retaining walls)

The TEMPE PAVILLION (n. 6) and ROCCABRUNA (n. 29), located on the opposite sides of the Villa, east and west, were both conceived as watch-towers, and even shared the same type of opus sectile pavement, in black ardesia and yellow marble, a sign of their similarity.

Fig. 22 - Praetorium: in the lower part the substructures, on top the panoramic Pavillion
Another architectural device was the use of a double hidden access, made of two entrance doors flanking a central axial perspective, as we can see in the CASINO WITH SEMICIRCULAR ARCADES (n. 20).

Let us see now in detail the three different types

1 - The servant's quarters.

They were not free-standing 'buildings', but were a series of rooms gained within the substructures or the retaining walls of Hadrian's Villa. They were in the HUNDRED CHAMBERS (n. 16), in the SUBSTRUCTURES OF THE PRAETORIUM (n. 27) and in the WEST SUBSTRUCTURES OF THE CANOPUS (n. 28a), which were built in the same way. They had several floors (fig. 22), whose beams were supported by 'mensole', large squared blocks of travertine or marble. Wooden stairs and balconies connected rooms and floors. They were simply paved with coccio-pisto, or opus spicatum, or sometimes with very coarse mosaic, cheap materials which we saw being typical of the buildings belonging to this group.

Fig. 23 - Firemen's Headquarters, room CV25: multi-seater latrine

It seems that the walls were not plastered, but we know that the HUNDRED CHAMBERS had an hollow space in the back, in order to isolate the rooms from humidity. It is possible that the same thing happened in the substructures of the Praetorium, which are very little known and studied.

Fig. 24 - Vestibulum: one of the subterranean service corridors
The latrines of these buildings were multi-seater (fig. 23), and this means that a large number of people were living there, confirming their low social status. Of course there were no winter heating plants. The great number of these rooms, their location and their minimal decoration show that they were meant for the slaves and the servants of the Villa. This is confirmed by the fact that these buildings were directly linked to the subterranean road network (fig. 24), such as the large network of tunnels and cryptoporticoes that from the HUNDRED CHAMBERS (n. 25) reached the VESTIBULUM (n. 25) and the praefurnia of the GREAT and the SMALL BATHS (n. 26 and 24). They were also linked to the subterranean road that passed underneath the PIAZZA D'ORO (n. 15) and reached the GREAT TRAPEZIUM (n. 34). Access to the servant's quarters usually was subterranean, and the paths were completely separated from those leading to the secondary or the noble quarters of the Villa. These last had open air access paths, quite scenographic and monumental.

To this group of buildings also belonged the FIREMEN'S HEADQUARTERS (n. 22a), a building featuring a very simple architecture, with different floors that could be reached with wooden stairs;

Fig. 25 - Hospitalia, room HS15: multi seater latrine
it was entirely paved with opus spicatum (with a coarse mosaic near the 'multi-seater' latrine).

2 - The secondary buildings.

The were paved with black and white mosaic, and absolutely had no opus sectile or polychrome mosaic. Here, too, there were multi-seater latrines (fig. 25), and no winter heating plants. Decoration and finishing were much better compared to the servant's quarters, but not luxurious. Mosaics had vegetal or geometric patterns, walls were decorated with simple frescoes.

Secondary buildings were meant for high ranking personnel, such as liberti, priests, bodyguards, officers. It has been suggested that in the Hospitalia lived the Praetorian Guard of the emperor. To this group belonged the FARMHOUSE NEAR PIAZZA D'ORO (n. 15b), the GREAT BATHS (n. 26), and the complex formed by HOSPITALIA (n. 8) and IMPERIAL TRICLINIUM (n. 7), linked to the CRYPTOPORTICUS WITH MOSAIC VAULT (n. 13). The architecture of these buildings was simple, with squared shapes, no monumental entrances, no panoramic view, nothing more than what was necessary. Access roads and passageways were in the open but hidden, and separated from those leading to the noble buildings. There was a connection with the subterranean road system.

The GREAT BATHS (n. 26) were paved with simple black and white mosaics, and therefore must be considered as the thermal plant serving the inhabitants of the secondary buildings and also the slaves. In fact all other thermal plants in the Villa had marble opus sectile pavements, and therefore they belonged to the group of noble buildings. Many scholars believed that the Great Baths were used by men only, while the neighboring Small Baths were just for women.

Fig. 26 - Winter Palace, room PE40: holes left from the 'grappe' supporting the wall marble revetment
Their decoration clearly shows that the two thermal plants were meant for different social status, not different gender.

3 - The noble or imperial buildings.

Their decoration was extremely refined and luxurious: pavements were in marble (opus sectile), or in polychrome mosaic, sometimes enclosing precious panels in vermiculatum; black and white mosaics were used only in service rooms and passageways.

Opus sectile pavements employed marbles coming from caves scattered in the whole world, with a great variety of colours and patterns. The walls still bear traces of the nails (grappe) that supported the marble revetment, often reaching up to the ceiling (fig. 26). There were large panels, sometimes hollows for marble reliefs, as we can see in the CASINO WITH SEMICIRCULAR ARCADES (n. 20), in the WINTER PALACE (n. 22) and in the ACCADEMIA (n. 30).

Fig. 27 - Winter Palace, room PE52: single seater latrine
In many different rooms still survive some fragments of frescoes, of stucco, of mosaic or 'tartari' (pseudo-grotto). The preciousness of decoration itself shows that these buildings were meant for the Emperor's use, and other features confirm their importance and rank. One is the presence of winter heating systems in non-thermal buildings, such as in the CASINO WITH SEMICIRCULAR ARCADES (n. 20), in the WINTER PALACE (n. 22), or in the upper floor of the GREEK LIBRARY (n. 10) and - possibly - in the ACCADEMIA (n. 30). Latrines always were 'single', one-seater (fig. 27): their decoration was very precious, with opus sectile marble pavements and marble revetment of the walls, exactly as in the other rooms of the buildings where they were located.

Fig. 28 - Imperial Palace, room PI25, so called Summer Triclinium
To the group of noble buildings belonged several thermal plants: the THERMAE WITH HELIOCAMINUS (n. 19), the SMALL BATHS (n. 24) and the small private therma of the MARITIME THEATER (n. 18). According to Piranesi, also the ACCADEMIA (n. 30) had a thermal plant. The noble buildings were always decorated with nymphaea, had dozens of niches for statues, and sumptuous open air triclinia, that are visible in different buildings of the Villa, such as the IMPERIAL PALACE (n. 12) where we have the so-called Summer Triclinium PI25 (fig. 28). Then there was another triclinium in the PIAZZA D'ORO (GOLDEN SQUARE) (n. 15), in the GARDEN STADIUM (n. 21), in the WINTER PALACE (n. 22) and in the CANOPUS (n. 28), which was the most monumental and spectacular of the whole Villa. Garden triclinia with waterworks were another 'must' in imperial estates. The Villa also featured a certain number of 'secret gardens' enclosed by walls and surrounded by porches (fig. 29), often decorated with a water basin at their center, which was reflecting the image of the buildings. This happens in the PECILE (n. 16), in the IMPERIAL PALACE (n. 12), at PIAZZA D'ORO (n. 15), in the GARDEN STADIUM (n. 21), in the VESTIBULUM (n. 25) and in the ACCADEMIA (n. 30).

Fig. 29 - Accademia, porch AC14: the wall surrounding the 'secret garden'
Noble buildings all had a dominant panoramic location, and made the most of the site, enhancing the view over the Tempe Valley or from the hill of ROCCABRUNA (n. 29). Porches allowed people to stroll from one building to the other almost without interruption. Entrance paths preferred a central axis, but used two dissimulated side access doors, which were meant as a security filter, as we can see in the CASINO WITH SEMICIRCULAR ARCADES (n. 20), in the GREEK and LATIN LIBRARIES (n. 10 and 9), in the lower floor of the WINTER PALACE (n. 22).

Noble buildings had monumental architecture and luxurious finishings: impressive halls, colonnades, niches and pedestals for hundreds of statues, water basins, fountains.

Plans were extremely sophisticated: no straight lines, but curves, apses, columns. Perspective views gave the impression of infinite space, frequently using apses with openings in their walls, which allowed an axial view inside the buildings (fig. 30).

Fig. 30 - Small Baths, octagone Hall PT19: a perspectic view through other rooms

During the reign of Nero was created a new monumental and scenic architecture, whose highlight was the Domus Aurea. This new spectacular architecture had a stylistic development under the following emperors, leaving behind the rigid symmetry of republican and augustan times. This is why in Hadrian's Villa perspectives and axiality were not rigid nor perfectly symmetrical, as could be seen in the previous republican villa. Perspective was varied, views unexpected and surprising, everything was planned to amaze visitors and guests. Even today.

Roofing featured the entire roman repertoire: domes, cross-vaults, barrel vaults, and the famous 'pumpkin' domes ridiculed by the architect Apollodorus of Damascus (fig. 31).

Fig. 31 - Piazza d'Oro (Golden Square), Vestibulum PO2: the 'pumpkin' dome
In these domes and vaults we can see the creativity but also touch and feel the inner strength of hadrianic constructions, still standing after centuries of neglect and theft of bricks and marbles. The most important architects of the Renaissance came to Villa Adriana because they wanted to understand the technical secrets of its buildings, and not only to draw plans.

The noble buildings in Hadrian's Villa were the following (listed in topographical order): the GREEK THEATER (n. 1), the PALESTRA (n. 2), the NINFEO FEDE (n. 3), the GREEK and LATIN LIBRARIES (n. 10 and 9), the COURTYARD OF THE LIBRARIES (n. 11), the IMPERIAL PALACE (n. 12), the so-called OUTER PERISTYLE (n. 8a), and the HALL WITH DORIC PILLARS (n. 14). Then there were the THERMAE WITH HELIOCAMINUS (n. 19) and PIAZZA D'ORO (n. 15). The fulcrum of the Villa was the artificial esplanade of the PECILE (n. 16), from which there was an access to the PHILOSOPHER'S HALL (n. 17) and the MARITIME THEATER (n. 18). West of the PECILE was the complex that we have identified as the IMPERIAL RESIDENCE, which had two different levels (see separate section for a detailed description). On the lower level was the CASINO WITH SEMICIRCULAR ARCADES (n. 20) (which was the atrium of the complex), then the GARDEN STADIUM (n. 21) (a 'secret garden', a peristyle with a summer triclinium) and the lower floor of the WINTER PALACE (n. 22): they were part of one single and indivisible complex, and were linked to a thermal plant, the SMALL BATHS (n. 24), through the QUADRIPORTICUS (n. 23). The CRYPTOPORTICUS OF THE GREAT BATHS (n. 26a), could be reached from other two noble buildings, the SMALL BATHS (n. 24) and the VESTIBULUM (n. 25), and gave access to the stairs climbing up to the upper floor of the WINTER PALACE (n. 22) and also to the PRAETORIUM PAVILLION (n. 27). On its upper level, the WINTER PALACE was also connected to the IMPERIAL PALACE (n. 12) and PIAZZA D'ORO (n. 15), and to the PRAETORIUM PAVILLION (n. 27).

Near the Pecile was located the main monumental entrance to the Villa, a paved road in a form of a rectangular ring, leading to the stairs of the VESTIBULUM (n. 25), from which could be reached the CANOPUS (n. 28) and the PRAETORIUM PAVILLION (n. 27). Another access road climbed to the higher part of Hadrian's Villa, where are located ROCCABRUNA (n. 29), the ESPLANADE (n. 29a), the ACCADEMIA (n. 30) and the ODEON (n. 32). From there it was also possible to reach the INFERI (n. 33) and the TEMPLE OF PLUTO (n. 36). From the PRAETORIUM PAVILLION an artificial terrace (n. 27a) overlooking the Canopus also reached the area of the substructures of the ACCADEMIA (n. 30).

Fig. 32 - Ninfeo Fede, opus incertum retaining wall, inherited from the previous republican Villa
4. The building phases and chronology of the Villa

Before Hadrian's Villa, there was a small republican villa which was later enclosed in the hadrianic buildings. Identified by Lugli at the beginnings of the XX century, it had the traditional plan of the roman domus, with a garden (the COURTYARD OF THE LIBRARIES n. 11), a basis villae (the CRYPTOPORTICUS WITH MOSAIC VAULT n. 13), and then an atrium with a tablinum opening on a peristyle surrounded by cubicula (the eastern part of the IMPERIAL PALACE n. 12).

In the area of Hadrian's Villa there are other structures of republican age, as a retaining wall built in opus incertum underneath the NINFEO FEDE (n. 3) (fig. 32); ancient drawings show that it was flanked by two semicircular nymphaea. Actually there was just one apsed nymphaeum on the northern side, built in opus reticulatum, while on the opposite side we can see a system of galleries excavated in the tufa rock, which lead up to the Terrace of Tempe. Another republican retaining wall is visible on the eastern side of the HOSPITALIA (n. 8) and a great nymphaeum in opus reticulatum was enclosed in the QUADRIPORTICO (n. 23) and re-used as northern wall of the SMALL BATHS (n. 24) (fig. 33).

We also have a small republican nymphaeum located in front of the main entrance to the MARITIME THEATER (n. 18). Part of the FARMHOUSE NEAR PIAZZA D'ORO (n. 15b) was of augustan age. Never was made a detailed survey of building techniques (we still rely on Lugli's ones) nor a diachronic map. Probably there are other republican structures, among which the underground water reservoirs with cuniculi (found near the GREAT BATHS n. 26), which are are typical of the republican age. (See Plate 8 - Map of the buildings of republican or augustan age)

Fig. 33 - The ancient republican nymphaeum built in opus reticulatum, re-used in the Quadriporticus as northern wall of the Small Baths.

Date and chronology of the hadrianic buildings mainly relies on the brick stamps published by Bloch in 1937; his work has never been updated. Brick stamps are very important, but none of them was found in half of the building of Hadrian's Villa (about 15 out of 30). Bloch wrote that the collection of brick stamps was not consistent and that sometimes old bricks with stamps were re-used in modern restorations! In this case only the analysis of the mortar can state if the wall where the brick stamp was found really is an ancient one.

According to the date of the brick stamps, the older buildings of the Villa are the MARITIME THEATER (n. 18) and the PHILOSOPHER'S HALL (n. 17), where have been found brick stamps with the date 117 A.D.

Bloch published a letter of Emperor Hadrian to the Delphians, from which we understand that his Villa was already used as imperial residence in 125 A.D. Bloch thought that Hadrian's Villa had three building phases: the first went from 117 to 125 A.D., corresponding to the first years of his reign. The second went from 125 to 132-134 A.D., and was linked to the dates of departure and arrival of Hadrian's long travels in the Empire. The third phase, dating from 133-134 to 138 A.D., corresponded to the final return of Hadrian and his death.

This theory, followed by Salza and other scholars, seeks a connection between building phases and the travels of the Emperor, but does not rely on archaeological evidence. For example, it is questionable the theory that the CASINO WITH SEMICIRCULAR ARCADES (n. 20) and the WINTER PALACE (n. 22) were built separately, and that only after many years they were linked together by the GARDEN STADIUM (n. 21). Actually, the three of them were part of one single complex, tightly interconnected and obviously built together.

The same happens with the HOSPITALIA (n. 8) and the IMPERIAL TRICLINIUM (n. 7), which were part of a single unit, as shown by their mosaics with identical workmanship values. For decades the IMPERIAL TRICLINIUM (n. 7) was linked to the TEMPE PAVILLION (n. 6), dating it accordingly to the brick stamps found in the latter. But the TEMPE PAVILLION was a noble building, paved with opus sectile and completely separated from the Imperial Triclinium, with different access paths.

We know very little about the building phases of the Villa because never was made a detailed archaeological survey of the buildings, studying their interaction and chronology. Same importance has the study of retaining walls, which belonged to different times and were surely built before the buildings they host: they were never studied or surveyed.

5. Conclusions

For the first time, my survey applied to the study of the Villa the principles of archaeometry; this should be a starting point for new analysis. Never has been made a detailed study of the Villa using information technology.

With new surveys it will be possible to give an answer to several questions. To understand the chronological phases of the different buildings and how they were modified or restored throughout the centuries. To understand their relationship with the subterranean road network; to reconstruct the decoration of pavements and walls, especially of the marble revetments. To understand the chronological sequence of the retaining walls and the artificial terraces with their buildings. To reconstruct gardens, parks, and follow the traces of aqueducts.

It must be created a data-base gathering new data and old information coming from ancient sources and previous literature connected with a GIS. It is necessary to draw new plans and make 3D virtual reconstructions and models.

This will give us a deeper knowledge of the state of conservation of the Villa, in order to preserve it for future generations.

Section 2 - Wall revetments | ^ Back to top