I Have a Theory
About that portico…. There are two types of classical architects, those who are troubled by the portico of the Pantheon—more specifically, its somewhat awkward relation to the intermediate block between it and the rotunda—and those who are not. I have been, it should be said, one of the latter, but I cannot help taking account of the many arguments against the portico, especially those of Mark Wilson Jones. So, in light of my meditations on emulation, let me offer a theory that might explain the anomalies as intentional, perhaps even essential to the building’s meaning.
Caveat lector: what follows is mere speculation. But in a case where no documentation exists as to intent, other than the material remains themselves, what else is one to do? The question is, does an explanation resolve a question in way that is, if not efficient, at least effective in tying up as many loose ends as possible (Ockham’s razor). I hope the following measures up.
Let’s start with the “dedication,” which fooled so many for so long. In no other case does a Hadrianic building invoke an older dedication so explicitly and prominently. Why would Hadrian have done it? To mask the innovation of his newer rotunda? Perhaps, but what if that dissembling were driven by a concomitant desire to recreate or rebuild what had actually been there, and append to it his own contribution? Little is known about the Augustan Pantheon, but it is presumed to have been a fairly canonical Roman temple, with portico and rectangular cella like the temple of Mars Ultor in the Forum of Augustus.
Augustus did, of course, defeat Marc Antony and Cleopatra’s forces at the battle of Actium, and thus absorbed definitively Egypt into the Roman Empire. What better way to concretize that absorption than a temple portico, its column shafts made of Egyptian granite? This early exercise in Egyptian import might explain the imprecision in the column shafts.
So, here is my conjecture about the Pantheon’s portico: that it is a literal, not metaphorical, rebuilding of the portico of the older temple destroyed by fire, and the employment of spolie from that building explains the lack of reconciliation with the intermediate block, and the discrepancies of column shalf/capital heights noted recently by Lothar Hasselberger. As reconstruction, it was allowed to be—even demanded to be—distinct or detachable from the rotunda-cum-block erected behind. The anomalies at the juncture, therefore, are not problems, but deliberate accentuations of differences.
This would be wholly within the framework of ancient understandings of emulation, neither archeological nor radical. They juxtapose and integrate disparate pieces to form a more ambitious whole. Se non è vero, è ben trovato.
PS: my book The Challenge of Emulation in Art and Architecture is scheduled to be published by Ashgate (UK) in November 2013