Bryn Mawr Classical Review

Bryn Mawr Classical Review 2002.08.39

Roman Architecture, Design Process and Professionalism: A Review of Aspects of Recent Work.  

Reviewed by Thomas Noble Howe, Art Department, Southwestern University (
Word count: 2274 words

Roman architecture was much more complicated, individualistic and inventive than Greek, or, for that matter, almost any tradition which came before it. Why?

A decade of recent work has brought important advances, summed up in particular by Mark Wilson Jones' Principles of Roman Architecture,1 in our understanding of the working methods of Roman architects, and may have brought us closer to answering this question by better understanding the nature of the professionals who designed these buildings and how they worked. These studies have tried to observe the standing monuments not just as "finished products" but as objects which may reveal something of the "generating processes" which produced them,2 that is, the process of design and alteration which occurs in the process of construction. They tend to concentrate on the practical aspects of measure and proportion in the design process but by doing so they open up opportunities for a more realistic and context-sensitive approach to the interpretation of architecture meaning.

Earlier studies have brought us closer to a realistic appreciation of the probable controlling geometry and design sequence in the cases of isolated buildings,3 but without extensive comparison between buildings we have not yet had a convincing presentation of what may have been "standard practice." The discovery of a number of architectural working drawings on building surfaces from the late 1960's at Baalbek, Bziza, Didyma, and other places, including probable drawings for the Pantheon pediment at Rome, have provided a vivid image of the design and working drawings and the character of their use of rule and compass.

The studies have a number of features in common. The first is that they concentrate on major Roman monumental buildings between the first and early fourth century A.D. Wilson Jones' work has the value of being a broadly based survey of monuments across the empire, and he restricts the survey of design strategies almost exclusively to large and complex buildings in brick-faced concrete with substantial ornamental details (i.e. orders) in cut stone (an exception might be the principia at Palmyra). These are therefore buildings which rarely had to make radical adjustments to the site and which have either brick faces or stone elements which are probably executed to precise dimensions rather than ad hoc.

The next feature of these studies is that they proceed from directly measured study of the monuments, and analyses are generally attempted in terms of ancient metrology. With Wilson Jones' survey of the metrics of a large number of monuments the use of the Roman foot (as far as it can be approximated with individual monuments) reveals some very clear patterns, or preferences, namely the strong preference for Roman designers to design, wherever possible, with major dimensions in simple whole numbers of feet, usually multiples of 10 or 12, or to a lesser extent 16.4 This also gives a clue to design process since wherever the dimensions of a monument can be imputed to be such simple dimensions these may represent the initial design assumptions of the building. For instance, with the design of centralized monuments, Wilson Jones has distinguished between externally oriented centrally planned buildings, such as the tombs of Munatius Plancus or Caecilia Metella, which have entrances that thrust inward and maintain a geometrically pure exterior, and internally oriented buildings, like the Mausoleum of Maxentius or the Pantheon, which have entrances which thrust outward, maintaining geometrically regular interiors.5 The simple whole number dimensions occur on the exterior of the externally oriented buildings and on the interior of internally oriented ones. There is also a tendency to prefer dimensions of a hundred (Munatius Plancus, Caecilia Metella) or a hundred and fifty feet (Pantheon, San Stefano Rotondo). This existence of the "ideal" dimensions in one location or the other deals with the simple fact that in actual executed architecture simple numbers or proportions can usually occur in only in a limited number of dimensions; as soon as one has to deal with wall thicknesses one has to accept the existence of certain less elegant dimensions. As Vitruvius says, with the usual lack of concrete illustrative clarity: "Now it is not possible to have the symmetries for every theater carried out according to every principle and to every effect. Instead it is up to the architect to note in which it will be necessary to pursue symmetry to make adjustments according to the nature of the site or the size of the project."6

Another feature of the approach is that "flaws or compromises must be identified for what they are."7 DeLaine's analysis of the dimensions of the Baths of Caracalla make it very plain that a mistake occurred in the laying out of the foundations of the apses of the natatio and frigidarium which was corrected only when the construction reached ground level, and one of the now best known examples is Wilson Jones' theory that the odd conjunction of the Pantheon porch to the rotunda is due to the necessity of adapting the design to the delivery of forty foot monolithic columns shafts rather than the projected fifty foot shafts.8

The ability to detect mistakes depends upon the ability to detect intentions, and one of the most significant features of this approach is the assumption that underlying most major complex monumental works of Roman architecture is an original geometrically and metrologically "ideal" plan (or more accurately "parti") which was modified in the course of construction. The significance of the newness of this analytical approach is that scholars may now not be looking for an ideal underlying plan, but a plan that is developed, and executed, as part of a process.

DeLaine's analysis of the Baths of Caracalla is significant in this regard in that it not only deals with errors and changes in plan in the course of construction but even points out that the fundamental process of "ideal" design of the main spaces must have proceeded in a sequence of geometrical moves, starting from a 200 x 200 foot square.9 Similarly Wilson Jones' analysis of two common methods of the laying out of civic amphitheaters or the process of designing the Teatro Marittimo at Hadrian's Villa or the annex at Baiae had to proceed with a series of compass and rule moves, which then gradually took into consideration wall thickness and mutual adjustments.10

This may be the most questionable aspect of the method for many, since the "ideal" dimensions may not be visible in any part of the executed monument, or in only a few parts. This might seem like an invitation to convenient fallacy, perhaps relieving the theorist-researcher from the necessity of matching theory to measured evidence. A significant part of the method therefore must be to find reasons for the discrepancies in order for the argument to be convincing. The reasons which can be deduced from the study of the monument can include the tolerances of execution, mistakes in execution, adjustments to site, and working out of logical inconsistencies within the original geometric conception itself.

And indeed it does not necessarily produce unambiguous interpretations of the original intentions. Wilson Jones' own interpretation of the Maison Carée at Nîmes does indeed demonstrate the probable existence of the double cube as a design intention in the façade (as opposed to a fortuitous outcome), but relies on the assumption of some very "near misses" in plan, i.e. adjustments in the course of execution. His interpretation of the round temple at Tibur as being based mainly on simple arithmetical relationships is juxtaposed with H. Geertman's geometrical interpretation with no clear demonstration of the superiority of either.11

Wilson Jones provides a functional definition of the distinction between geometrical moves in design, which could be produced only by compass and rule (curves and certain ratios of diagonals which produce ratios of square roots of 2, 3, and 5) and arithmetic, but he also argues that many designs relied on both types of exercises and that furthermore the distinction was probably not all that clear to ancient practitioners.12 Grids and ratios of 1:2, etc., are both geometrical and mathematical. The shapes of amphitheaters may have been created by swinging strictly geometrical shapes, but the division into equal exterior bays of whole numbers of feet (often twenty) shifts to arithmetic. Subsequent design moves in amphitheaters then often have to be "fudged," that is, are dependent upon these metrical decisions, rather than dimensioned on their own. For instance, radial walls of amphitheaters then need to be laid out perpendicular to the perimeter (as in most) or radial to an internal center (e.g., Arles), an approach which is essentially ad hoc and geometrical.

Taken individually the presence of "ideal" initial designs might not be convincing, but the large amount of material surveyed in Wilson Jones' work argues very convincingly that there was indeed something like standard practice and that it was widely spread across the Empire. Ultimately we need not doubt that for most designers an initial strong geometrical concept and whole number dimensions were a design goal, in fact a convenient design means.

These researches bring up a number of interesting questions and point new directions for further research. The most intriguing and significant might be that we may begin to argue that there was in fact a real profession of architecture, dominated by something like the type of educated and practically experienced person pictured in Vitruvius' de Architectura. In particular the type of intellectual gamesmanship required by some of the geometrical "moves" required in some of the designs (e.g., the Teatro Marittimo at Hadrian's Villa, where the three rings all are designed to be equal in area) demand the kind of education in Euclidean geometry which was common enough to the liberally educated classes but quite beyond the obvious geometry known to the craftsman or semi-educated. These were presumably of the class of apparitores, the trained technicians who assisted magistrates in the administration of municipal and military activities.

If this argument can be made, it also brings up the question of how much of Roman architecture was created by these "professionals?" Vitruvius makes it quite plain that all sort of persons advertised themselves as architects, including the incompetent (inperitus), the "ambitious" (those who curry favor and commissions by "doing the rounds" = ambitio), and the amateur who may design his own house (and may thereby do much better than if he applies to an incompetent architect) (6.praef.5). When we drive around a modern American suburb today we can usually tell quite quickly which houses (if any) are designed by architects, which by contractors. Can we tell if an architect designed a military camp? A villa? A townhouse-domus?

It may be arguable that this trained class really did dominate the most significant and creative Roman architecture, giving something of the inexhaustible inventiveness of modern architecture. It also raises the question of chronological development. Can further study distinguish this class from Hellenistic or Republican builders? If the class came about largely in the late Republic and early empire, did Vitruvius' vision of the liberally trained professional play some role in the creation or reformation of the profession?

These studies may do much to explain the ambiguous assertions in Vitruvius that designs always need to be modified or adjusted to circumstances. They also may aid us in evaluating the relationship between practicality and symbolism in choosing dimensions and proportions in design. The relationship may be that they are essentially integral. Scholars may be encouraged to abandon some of the more elaborate number and proportion theory in explaining meaning in design (like the Golden Section) or to relegate them to virtuosic intellectual games in buildings where they may be demonstrated to occur. The general impression is that given by Vitruvius who sees symmetry (commensurability) as embodied in all of "well-shaped" nature (not just the human body) and hence equally embodied in well-ordered architecture. It may be then that architects, who could shape buildings with as many simple whole number dimensions involving "perfect" or natural numbers like 6, 10, 12, 50 or 100 as possible, were at once achieving what they thought to be practical order and something very much like natural order at the same time.

From both DeLaine and Wilson Jones, well as others, we are getting a clearer idea of what may have functioned as "rules of thumb": in DeLaine, near-standard ratios of vault span to wall thickness (usually c. 1:10), from Wilson Jones some practical procedures for shaping entasis (carving the shaft as the junction of a cylinder and cone and then rounding off the curve intuitively), the "cross-section rule" (in which the height of most Corinthian capitals equals the axial width of the abacus), and the rule that the height of the shaft is five-sixths the total height of the columns (i.e. allowing for substantial differences in the relative heights of base and capital).

What these sharpening images of practical rules of thumb and thorough mastery of controlling geometry give us is an enhanced appreciation of the ability of "professional" Roman architects to achieve innovation and personal expression while working within normative rules. As Mark Wilson Jones put it quite succinctly, the reason for the popularity of the cross-section rule in the design of the Corinthian capital is that "it did not govern the appearance of the capital except within very broad limits; and there were other proportions (such as slenderness) which had a more immediate impact on appearance."13

These highly positivistic studies are shaped largely from the point of view of the workings of Roman designers, and as a result we maybe getting a clearer image of a profession that created a rich repertoire of design by means of complicated combinations of simple rules and dimensions.


1.   Mark Wilson Jones, Principles of Roman Architecture (Yale University Press, London and New Haven, 2000).
2.   Janet DeLaine, The Baths of Caracalla, A Study in the Design, Construction and Economics of Large-Scale Building Projects in Imperial Rome, (JRA Supplement 25, Portsmouth RI, 1997), p. 9.
3.   E.g., F. Rakob, W.-D. Heilmeyer, Der Rundtempel am Tiber in Rom, (Mainz, 1973), id. "Metrologie un Planfiguren in der kaiserzeitlichen Bauhütte", Bauplanung und Bautheorie in der antike (Darmstadt, 1984), 22-237; idem, Die Piazza d'Oro in der Villa Hadriana bei Tivoli (Diss. Technische Hochschule Karlsruhe, 1967), G. Cozzo, Ingegneria romana (Rome, 1928, 2nd ed. 1970).
4.   Wilson Jones (2000), pp. 74 ff.
5.   M. Wilson Jones, "Design Principles in Roman Architecture: the Setting Out of Centralized Buildings," PBSR 64 (1989), 106-51; idem (2000) p.74.
6.   5.6.7, trans. I.D. Rowland, in Rowland and Howe, Vitruvius, Ten Books on Architecture (Cambridge University Press, 1999).
7.   Wilson Jones (2000), p. 11.
8.   DeLaine (1997), pp. 64-65; M. Wilson Jones, in P. Davies, D. Hemsoll, Wilson Jones, "The Pantheon: Triumph of Rome or triumph of Compromise?" Art History 10 (1987), pp. 133-53, idem, (2000) 199-206.
9.   DeLaine (1997), pp. 45-68, esp. Fig. 32.
10.   Wilson Jones (2000), 87-100.
11.   Wilson Jones (2000), pp 66-68; 103-106; H. Geertman, "La progettazione architettonica in templi tardo-repubblicano e nel De Architectura di Vitruvio," Munus non ingratum; Proceedings of the International Symposium on Vitruvius' De Architectura and Hellenistic and Republican Architecture (BABesch Suppl. 2, Leiden, 1989) 154-177.
12.   The distinction follows a distinction made by Vitruvius, 9.praef. 4-5, who demonstrates how to double the area of a square by constructing a square on its diagonal: "No one can find the result by means of arithmetic alone."
13.   Wilson Jones (2000), p. 146.

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