A HISTORICAL AND TOPOGRAPHICAL OVERVIEW OF THE DOMUS AUREA

Whatever else can be said of Nero's reign, it must have been interesting. Never before nor since has an autocrat been so wholly devoted to the arts, regardless of cost and generally to the exclusion of all else. This phenomenon is well documented, both in ancient literary sources and in the artistic record, not only in terms of Nero's effusive patronage of the arts in all media, but also in terms of the high quality and often audaciously experimental nature of the works executed under his auspices. As was commonly the fate of emperors whose damnation was important to the subsequent dynasty, much Neronian art was systematically destroyed or reworked, leaving only a specter of its original grandeur for modern scholars. This is as true for Nero's architecture as for any art form – a tragedy in the face of a substantial literary record specifically focused on his building projects. In any case, and not surprisingly, the ancient literary tradition focuses especially on Nero's most personal building project – his palace, the Domus Aurea. That Nero would construct a building suitable for his grandiose notion of himself is perhaps predictable and, as far as we can tell, it was a project to which he was devoted from the earliest possible moment in his reign.

PRE-NERONIAN TYPE X AND RELATED MASONRY (ROOMS 65–80)

The Type X project is the most problematic and controversial phase in the Esquiline Wing (Figs. 11 and 12). It ought not be, however. Missing or encrusted facing means that Type X cannot be described in detail as a masonry type, but the chronological position of the Type X project relative to the other phases in the Pentagonal Court is unambiguous. Type X is a distantly pre-Neronian construction, reused by Severus and Celer to form all of the Northwest Group (Rooms 65–70) of their Pentagonal Court and the west half of the North Group (the North Group is Rooms 71–83; the Type X part is Rooms 71–74, 76 and the west half of Room 80, as indicated on Fig. 11).

The masonry details are described later, but because the Type X phase is controversial, an emphatic summation of what the data tell us about it may be useful from the outset. The Type X remnant provides two sides of the Pentagonal Court, the largest and externally most distinctive design feature in the Neronian palace (the Pentagonal Court). Given that, it must seem that the Type X was an integral part of the Neronian design and must perforce have been built as part of the Neronian project. This is false; the Type X segments were reused by Severus and Celer, not built by them.

MASONRY IMPLICATIONS FOR THE DESIGN OF THE OCTAGON SUITE

Besides the dome itself, the most important architectural features of the Octagon Suite are the vault haunch clerestory windows over the extrados of the dome and the groin vaults in Rooms 123 and 125. The groin vaults are the earliest known examples of this motif in Roman concrete, discussed in greater detail in Section 2 of this chapter, but the vault haunch clerestory windows are more informative as far as the masonry chronology of the Esquiline Wing is concerned. They are integral to the whole design concept of the Octagon Suite, both because they bond to all surrounding masonry and because they play an important rôle in the lighting system. They not only light the radiating rooms, but also help lighten the appearance of the dome when viewed from inside Room 128 by letting light stream into the radiating rooms above the vault. They give the viewer in Room 128 the sense that there is nothing above the vault at all, disguising the fact that that is where the structural system for the vault actually is.

Except for the groin vaults, most major features of the Octagon Suite have to do with lighting. The visual effect of a feather-light dome, appearing to hover in a sea of light all around it, is almost mystical. It is similar in visual impact to trompe l'oeuil painting, clever and wonderful.

OVERVIEW OF THE NERONIAN WEST BLOCK AND THE WEST COURT

As Figures 6 and 11 indicate, Severus and Celer found a number of standing buildings in the area of the West Block when they began their project. For the most part, their procedure is easy to reconstruct, consistent with their practice throughout the Esquiline Wing. They had their own conception of what they wanted to build here, which, as I argue presently, was a reasonably canonical patrician villa suburbana. This design is most recognizable in the original Domus Transitoria project (Neronian phase 1), but was substantially modified in the Domus Aurea project (Neronian phase 2). Because Severus and Celer were creating an imperial residence, the earlier buildings they found on the site were generally incompatible with their needs, requiring widespread razing. Not only does Figure 29 indicate the original Neronian design, but also the Neronian parts represent the scale of the razing required to clear the site for Severus and Celer's design. The area in question is interesting in itself. Keeping in mind that Neronian phase 1 was the Domus Transitoria project, that is, before the great fire of a.d. 64, Severus and Celer did not have a completely free hand over the entire Esquiline hill, but had to make do with whatever parcels of land Nero could obtain for them. Apparently, this did not include some of the commercial properties in the Pentagonal Court area, nor whatever stood in the area of the East Block.