Hadrian’s Villa

Hadrian’s Celestial Architecture (based at the University of Virginia; PI: B. Frischer; Consultants: M. De Franceschini, C. Leitz, J. Miller; Technical Lead and co-PI J. Fillwalk)


Hadrian’s Villa is the best known and best preserved of the imperial villas built in the hinterland of Rome by emperors such as Nero, Domitian, and Trajan during the first and second centuries CE. A UNESCO World Heritage site located ca. 18 miles east of Rome at Tivoli, Hadrian’s Villa covers some 120 hectares and consists of 30 major building complexes. Built during Hadrian’s reign from 117 to 138 CE, and perhaps in no small measure designed by the emperor-architect himself, the site continued in use as a government retreat for more than a century. It was rediscovered in the 15th century and in recent decades has been the object of intense study, excavation, and conservation.[1]

From 2007 to 2012, with the generous support of a private donor and the National Science Foundation (grant #IIS-1018512), the Virtual World Heritage Laboratory at the University of Virginia and a team of over 35 scientific consultants used 3D Studio Max software to create a 3D reconstruction model of all the terrain and buildings on the site. The Max model is best suited for still and video renderings (e.g., https://vimeo.com/36579951), not for real-time interactive exploration of the virtual reconstruction (cf. figure 3).

Figure 3

Figure 3. Rendering using the 3D Studio Max model of a digital restoration of the lower rotunda of the structure now called “Roccabruna” at Hadrian’s Villa. The building was despoiled of its floor, wall, and ceiling decorations.  The restoration reflects the interpretation of project consultant Marina De Franceschini and Giuseppe Veneziano.[2] The candelabra and bases in the niches were found here and are now in the Vatican Museum. A trace of blue paint on the dome suggests that the iconography was based on the “Dome of Heaven” motif. The rendering shows the scene at sunset on the summer solstice of 130 AD when the light of the sun came through the front door and illuminated the statue in the niche opposite. Light also penetrated a conduit running through the cupola from the facade to the interior. From there, it was focused on the zodiacal sign of Gemini over the statue. June 21 is the last day of Gemini. The exact position of the sun could be determined from NASA’s Horizons database. Source: Virtual World Heritage Laboratory, University of Virginia.[3]

In 2011 and 2012, in partnership with the IDIA Lab of Ball State University the 3D model was converted to the game engine Unity3D (figure 4). This makes it possible for the model to be explored interactively over the Internet and for the world to be populated with avatars representing the members of the imperial court residing at the villa.


Figure 4.  A screen capture of an interactive session of the virtual world of Hadrian’s Villa, a Unity3D app. We see an avatar of Hadrian strolling under the colonnade of the virtual Canopus while a Non-Playing Character in the guise of a gardener is at work in a flowerbed. The solar tracker has set the date for June 1, 130 CE (Julian calendar) at 4:54 pm. Source: Virtual World Heritage Laboratory, University of Virginia.

The virtual world runs in HTML and takes advantage of a project website which provides the information needed to understand the villa and the 3D reconstruction (http://idialabprojects.org/hvtest/login.php: user id= “user’; password= “DHVP”).  At any point, the visitor to the virtual world can click on a menu bar or object and access information useful to understand what he is seeing (for a screen capture of a typical session, see: http://www.youtube.com/watch?v=AtuWYnYU8Eg). The conversion to Unity3D served three related purposes: (i) making the Max model available on the Internet so that it could be interactively explored at no cost by people around the world; (ii) testing recent scholarly hypotheses by Ytterberg (2005) and Chiappetta (2008) about how circulation around the villa was managed for the six major groups of people using the villa; and (iii) testing the relative advantages and disadvantages of teaching the villa in the college curriculum by using three variations on Problem Based Learning: face-to-face instruction, 2D web-based learning, and learning in the virtual world.[4]


Proposed New Project

Recent research has established that Hadrian applied his expertise in astrology to the design and orientation of buildings he commissioned  including, notably, the Pantheon (Hannah 2008, 2011) and the Mausoleum in Rome (Hannah 2011); and the Temple of Apollo and Roccabruna at Hadrian’s Villa (De Franceschini and Veneziano 2011).[5] These structures turn out to have significant alignments to recurrent  events such as sunrise and sunset on the solstice. The Hadrian’s Villa Project proposes to build on this research by exploiting its recently developed virtual world reconstructing the entire villa for an intensive search of possible celestial alignments incorporated in the plan of this large, but limited, area. This is empirical research so it is impossible to know in advance whether or not new alignments will be found. There are possible outcomes, all worthy of being reported. Firstly, new solar alignments may be found. The significance for scholarship would be that this would add new evidence that Hadrian was especially interested in the cult of the sun god. This would not be surprising in view of the close connection between the imperial cult and the sun god (cf. K. Scott, “Plutarch and the Ruler Cult,” TAPA 60 [1929] 117-135; H.  P. L’Orange, Studies  in  the Iconography of  Cosmic Kingship in the Ancient  World [Oslo, 1953]) and the role of the sun in the Roman religion generally (cf. M.R. Saltzman, “New Evidence for the Dating of the Calendar at Santa Maria Maggiore in Rome,” TAPA 111 [1981] 215-227. Secondly, new alignments involving celestial features other than the sun may be found. This would be significant because, as noted, the alignments in Hadrianic architecture found to date are limited to the sun. Hadrian’s passion for astrology could explain the presence of alignments with the moon, planets, and stars that play a role in Roman astrology. On the role of the sun and moon in Hadrianic theology see   K. Pratt, “Rome as Eternal,” Journal of the History of Ideas 26 [1965] 25-44. Thirdly, no new alignments may be found. Given the fact that the villa architecture dates exclusively to the age of Hadrian and that the entire area will have been thoroughly investigated, this finding could be a strong caution against overestimating the role of astrological thinking in Hadrianic architecture around the Roman world. Since Hadrian was one of the most active patrons of buildings in Roman history (for details, see the book by our consultant Mary T. Boatwright: Hadrian and the Cities of the Roman Empire [Princeton UP, Princeton 2002] ), this should interest a wide range of Roman historians and archaeologists.

To do this, we begin by enhancing our existing celestial Unity3D application, which is limited to the year 130 CE (Common Era) and includes only the sun. Enhancements will include: making the entire villa freely available on the Internet by creating a web player version of the existing Unity3D executable; using NASA’s Horizons database to add the other celestial features (moon and planets) that were important in Roman and Egyptian astrology; and expanding the time range to include the whole period of the villa’s planning and use from 117-138 CE. This new app will then be used, in conjunction with light sensors we will also develop for placement in doorways and windows, to automatically generate a set of alignments between celestial and built features at Hadrian’s Villa. We will run the new app for the year 134 CE. In a few minutes, the celestial features will move through the sky of that year. As they do so, the light they radiate will strike any sensors we have pre-set in their paths. When a hit occurs, it will be logged with time, place and celestial object. Consulting experts on the religious calendars of ancient Rome (Prof. John Miller, Chair, Department of Classics, University of Virginia) and Egypt (Prof. Christian Leitz, Chair, Department of Egyptology, University of Tuebingen) will check the log and give advice on which alignments may have cultural significance as opposed to those that are the result of pure chance. Given the recently-established importance of solar alignments in buildings designed or commissioned by emperor-architect-astrologer Hadrian, we are optimistic that new discoveries will emerge. Indeed, during our current NSF-sponsored project we have already found several new alignments. For example, in the recently excavated Antinoeion, at sunrise on July 20 the sun casts a shadow down the middle of the temple in which is housed a colossal statue of Antinous-Osiris (figure 5). As Prof. Leitz has noted, this alignment is probably not coincidental because in the 130s CE, July 20 was New Year’s Day on the Egyptian calendar, a day sacred to Isis and Osiris.


Figure 5. Left: view of the shrine of Antinous-Osiris in the Antinoeion of Hadrian’s Villa. The solar tracker has set the date for July 20 in the 130s CE; the hour is 4:30 am (sunrise). The arrow at A marks the shadow of the obelisk (seen in the right view), which is cast down the middle of the facade of the shrine, including the statue of Antinous-Osiris (found nearby and now in the Vatican Museums). The arrow at B marks the sunlight that silhouettes the statue. Right: view in the opposite direction. The arrow at C marks the rising sun seen over the roof of the nearby building known as the Tre Esedre. The arrow at D marks the Obelisk of Antinous thought to have originally been erected in this spot and now on the Pincian Hill in Rome. Source: Virtual World Heritage Laboratory, University of Virginia.

Importance of Virtual World Technology

Virtual World technology is a critical support for the proposed study for four reasons. First, the NASA Horizons database gives positional data for celestial objects in quantitative form. For a visualization of how the relevant celestial bodies appeared within a built feature on earth we need a dynamic 3D model of the kind supplied by Virtual World technology. This is important for several reasons, of which the most obvious is that absolute sunrise and sunset must be adjusted to the specific conditions of a building, whose line of sight to the horizon is generally blocked by neighboring structures. For this to be possible, one must combine the NASA data with the Virtual World reconstruction of the site. Secondly, because of the precession of the equinoxes, the position of the sun and stars changes over a cycle lasting 26,000 years. Thus to experience the night sky as it appeared in the reign of Hadrian requires that we create a computer simulation of the kind we have already made for the sun and now propose to extend to the other celestial objects with astrological significance. Moreover, Horizons generates information for a specific feature at a specific date and place on earth. Since we are looking at all possible alignments of many features with 30 buildings scattered over 200 acres, it would take an inordinate amount of time to make calculations one by one. Finally, we are interested not only in the quantitative investigation of alignments but in their humanistic interpretation. For the latter, being able to re-experience the alignment of a celestial object with a built structure is a critical part of determining whether a relationship is random or culturally significant.


The results will be written up by the research team as a scholarly article and submitted for consideration to a major journal in the field of Roman archaeology such as the Journal of Roman Archaeology or the Memoirs of the American Academy in Rome. It is difficult to know in advance where one will publish the results of empirical research, or how many publications may result. The promise of a scholarly article submitted for consideration to a major journal in the field is a minimal goal that will be achievable no matter what the results of the study. In terms of medium, the journals referenced are all print-based.


[1] For a survey of recent work, see Mari, Z. 2010. “Villa Adriana. Recenti scoperte e stato della ricerca,” Ephemeris Napocensis 20: 7-37.
[2] See De Franceschini, M. and G. Veneziano, 2011. Villa Adriana. Architettura celeste. Gli secreti degli solstizi (Rome).
[3] For the Horizons web tool, see [anon., n.d.]. NASA Horizons System. http://ssd.jpl.nasa.gov/?horizons (seen May 1, 2012).
[4] Chiappetta, F. 2008. I percorsi antichi di Villa Adriana (Rome).Ytterberg, M. 2005. “The Perambulations of Hadrian. A Walk through Hadrian’s Villa,” Ph.D. dissertation, University of Pennsylvania.
[5] Hannah, R. 2008. Time in Antiquity (London). Hannah, R. 2011. “The Role of the Sun in the Pantheon’s Design and Meaning,” Numen 58: 486-513. De Franceschini, M. and G. Veneziano, 2011. Villa Adriana. Architettura celeste. Gli secreti degli solstizi (Rome).