The Pantheon: From Antiquity to the Present

This long-awaited volume is the only published collection on the Pantheon covering the building’s history from Agrippa to the present. Considerations of the AJA’s readership lead me to focus on the first six of 12 essays, those covering the building in antiquity. The second six, by Thunø (the medieval Pantheon), Nesselrath (Renaissance), Marder (17th century), Pasquali (1700–1820), Williams (19th century), and Etlin (the modern age) are outstanding in their own right but have been adequately treated by other reviewers. Perhaps by design, the chapters on antiquity present a united front on certain scholarly developments. This unity and the cautious incrementalism it engenders reflect an appropriate fine-tuning of genuine epistemic advances from the last two decades, but the result is sometimes static and repetitive.

La Rocca begins with an essay on Agrippa’s Pantheon. The discovery in the 1990s of an earlier entrance staircase underlying the High Empire one almost assures that the Agrippan building faced north like its replacement. La Rocca plausibly envisions the paved zone excavated beneath the rotunda floor as a space functionally comparable to its successor, even if it lacked a massive concrete vault. But his proposed proto-rotunda—with a broad annular timber roof surrounding a small circular courtyard (the proto-oculus)—is strange. His single comparandum, a structure at Chester with a mandorla-shaped plan (67–8), had a double-pitched annular roof and radial walls sectioning the inner space like bulkheads: hardly a unitary space. His intuition that the Pantheon’s radial divisions echoed the celestial partitions of Etruscan divination is interesting; McEwen (“Hadrian’s Rhetoric I: The Pantheon,” RES: Anthropology and Aesthetics 24 [1993] 55–66) has made essentially the same argument. But it does not square with La Rocca’s cluttered reconstruction. I prefer the simpler competing notion of a circular, hypaethral court surrounded by an annular portico. If opus sectile adorned the proto-rotunda’s floor, as soundings may suggest (L. Beltrami and P.O. Armanini, Il Pantheon [Milan 1898] 37–8), that fact is untroubling; colored marble was not always protected from the elements but appeared, for example, in the orchestras of many Roman theaters. A popular hypothesis associating the Pantheon with the apotheosis of Romulus near a marsh called the Palus Caprae receives La Rocca’s approval, but it may need revisiting. A recent geomorphological survey demonstrates that the Pantheon’s site was on a rise, not a depression; its author displaces the marsh eastward (R. Leonardi, “Sondaggi lungo la tratta T2: Caratteri ambientali e aspetti topografici del Campo Marzio in epoca romana,” in R. Egidi et al., eds., Archeologia e infrastrutture: Il tracciato fondamentale della linea C della metropolitana di Roma. Prime indagini archeologiche [Florence 2010] 82–92).

Hetland reiterates and reinforces her important previous work on the dating of the existing Pantheon. Her argument that the building’s known brickstamps point to its inception under Trajan (ca. 112–114 C.E.) with a Hadrianic completion date (ca. 123–124 C.E.) is uniformly accepted among this volume’s authors.

Martines addresses the form and meaning of the Trajano-Hadrianic Pantheon, expressing its design in simple relational terms of Archimedean geometry and emphasizing the significance of the “perfect” number of 28 coffers in a row. There follows a discussion of the rotunda’s hollow, three-tiered “diaphragm structure” as compared with the aula at Trajan’s Markets, the Canopus at Tivoli, and especially the octagonal hall of the Domus Aurea. Martines argues that both these centralized domes were built in two parts: a lower zone with minimal centering, its thin incremental applications of concrete simply corbeled inward to form the intrados; and the upper calotte, which required scaffolding raised from the floor (129–30).

Waddell’s essay is oddly perfunctory. Overlapping considerably with Martines’ chapter, it enumerates the Pantheon’s basic design and structural elements, citing well-known parallels (and missing a few—e.g., the tholos with porch in the Largo Argentina). By contrast, DeLaine’s chapter is refreshingly new. Applying techniques she has refined over decades of architectural analysis in Rome and Ostia, she produces time and labor estimates for the Trajano-Hadrianic Pantheon, concluding that its labor requirements were modest when compared with the nearly contemporary Baths of Trajan and Temple of Venus and Roma (192). Perhaps 240 or fewer men were at work on the Pantheon at any given time, less than a tenth of the total DeLaine estimated in her monograph on Caracalla’s baths, which were of a scale comparable to Trajan’s.

Wilson Jones’ chapter builds on his already substantial contributions to Pantheon scholarship. The building’s south structure, he notes, was bonded to the rotunda with a “bridge,” implying that the whole thing functioned as an emergency buttress to counteract cracking that emerged on the rotunda’s south side during construction (201–2). There follows a discussion of the Pantheon’s east stairwell, where it is evident that the intermediate block was only bonded to the rotunda in its lower zone, and built against it farther up. Wilson Jones then augments the “compromise hypothesis” he has propounded since the 1980s: the proposition that the building’s porch and intermediate block, though designed for an order of 60-foot columns, were ultimately scaled down to accommodate 48-footers, perhaps because of a supply problem. The compromise solution altered the design scheme, disrupting the overall aesthetic of the facade. As he reads it, the evidence allows that the intermediate block’s construction was halted halfway up because of the emerging crisis then quickly resumed without immediate resolution. It was completed only when the compromise had been reached.

Wilson Jones, like his colleagues, accepts the minimalist, two-phase dome construction model advanced by Martines—suggesting additionally that if Trajan’s architect Apollodorus of Damascus was responsible for the existing Pantheon’s original design, as Hetland and her supporters suppose, then his noted wizardry with timber construction qualified him to design the dome’s centering (228). It puzzles me that so few architectural historians care to follow through on their centering hypotheses. Martines seemingly relegates centering to the banausic realm of the craftsman: ingenious, to be sure, but as the province of the bricoleur (to use Levi-Strauss’ parlance) carpentry need not interfere with the architect-scholar’s higher order of thinking. Wilson Jones more readily acknowledges that logistical design is profoundly embedded in formal design, yet he, too, is disinclined to envision in detail the bipartite scheme advanced relentlessly in this book.

Never mind the upper calotte of the dome, which everyone agrees required substantial centering; let us consider the lower zone. Without strongly resistant shuttering, the freshly laid concrete was subject to plastic deformation, the natural displacement of fresh, uncured concrete under stress. Such deformation continues after initial setting, often for weeks or months. Thus, with concrete, a Brunelleschian approach employing movable, lightweight formwork is out of the question. Like any heavy material augmented in horizontal layers, the dome’s concrete deflected laterally; the remedy was necessarily to build a strong, stiff dam to retain it. During construction, each stepped tier of the dome’s lower part can be understood as a flat “rice paddy” on a slope, requiring a substantive retaining wall at its borders; on the outside this wall was a sturdy ring of opus latericium at each level. The inner “hillside”—the formwork that defined the dome’s intrados—demanded comparable resistance to the lateral thrust; even a deformation inward of a few inches would severely compound errors in the dome above. Moreover, the complex design of the coffers required special molds that were probably too cumbersome to move during construction. How, then, was this shuttering held in place, or the necessary retentive resistance achieved, without either a massive ring scaffold rising from the ground, as Heene has proposed (Baustelle Pantheon: Planung, Konstruktion, Logistik [Düsseldorf 2004]), or a substantial compression ring of trussed timber beginning at the dome’s springings?

The fact that the finished dome is geometrically true—far truer, for example, than the much smaller dome of the “Temple of Mercury” at Baiae, which slumped dramatically and irremediably during construction—evokes a thicket of carpentry marshaled stubbornly against any wayward tendencies in the concrete. So, too, does the necessity of decorating the dome. Properly stripped and skeletonized after the concrete had cured, a full scaffold or flying centering would have supported trestles for the dome’s stuccoists and painters. Finally, the attendant need for cranes around the periphery of the rising dome to raise heavy timbers into place might partly account not only for leaving the intermediate block half-built until a late phase but also perhaps even for limiting the height of the south structure: the cranes’ long guylines needed clearance to the ground in all directions.

None of these criticisms diminishes the status of The Pantheon as an important milestone in the study of ancient Rome’s most celebrated building. Long in arriving, it is all the more welcome for that.

Rabun Taylor
Department of Classics
University of Texas at Austin
rmtaylor@austin.utexas.edu