Index | Article: "Scenes from a Design:The Plan of Saint-Urbain, Troyes" | page 2, page 3, page 4, page 5

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Figure 6

At about 10.58 meters per side, the crossing square is almost exactly 36 Roman feet of .294 meters. Thirty-six is, of course, six squared which, if you know your Augustine is the perfect number-both the sum and product of its factors. As he writes in The City of God:
'The works of Creation are described as being completed in six days, the same formula for a day being repeated six times. The reason for this is that six is the number of perfection ... For six is the first number which is the sum of its parts. that is of its fractions, the sixth, the third and the half, for one, two and three added together make six ... (T)he theory of number is not to be lightly regarded. since it is made quite clear, in many passages of the Holy Scriptures, how highly it is to be valued. It was not for nothing that it was said in praise of God, "You have ordered all things in measure, number and weight.""
Lay this 36 foot square out at the center of the plan. Rotating the diagonal (XZ) from the midpoint of the east or west side of the crossing square will yield the aisle dimension. This is followed by the sequence described above at Figure 4.

Sic et non

Three explanations of the way in which the main features of Saint-Urbain's interior might have been generated (the apse geometry will be discussed below): each involves elementary manipulation of the same units. However, the apparently minor differences in the sequence of geometrical 'events' reveals crucial differences in the conceptual orientation of the design.
In the first alternative, the 'mechanical' approach (figs. 3-4), the exterior and interior of the building derived from a single sequence of rotated squares, are conceived as an intimately related continuum. Design advances first from the 'outside in,' followed by steps that unfold from the 'inside out.' The crossing is not the cradle out of which the plan emerges but rather the byproduct of the geometry of the exterior. While this method appears to be the least accurate of the three options, small deviations from the measurements of the extant building that occurred in laying out the great squares of the exterior would account for the dimensional inconsistencies.

The 'square sequence' (fig. 5) generates dimensions and spatial blocks from a single square (S6) by means of a consistent procedure, the rotation of diagonal lines to produce golden section relationships. Stephen Murray has proposed that the golden section ratio of main vessel to aisle dimensions encodes a diagram of heaven into the plan at Amiens Cathedral. At Saint-Urbain, the method of generating the plan out from the crossing becomes a procedural expression of the subtly centralized character of its basilican plan. Located at the exact center of the plan with the nave and the choir balanced on either side and at the intersection of the four arms, the crossing is presented as the spatial focus of the church. This procedure, although extremely accurate in its relationship to the actual building, involves the most steps and an awkward transfer of key dimensions. While, to my mind, the square sequence does not offer a compelling design model, it does highlight the fact that Saint-Urbain's plan could be generated by a variety of methods. Further, as we shall see below, squares 5 and 6 were involved in the design of the apse and the west facade portals indicating that the rotational sequence may well have formed a geometrical subtheme in the generation of the plan. We assume that the master mason knew or discovered the most elegant, economical solutions to design the building's plan. This, however, must remain our own leap of faith.

Exterior and interior do not issue from a continuous geometric sequence in the 'symbolic generator' explanation (fig.6) although they are connected by golden section relationships. The plan unfolds from the center, the crossing, in a series of steps that operationally is identical to the 'mechanical version'. Setting the plan upon a symbolic foundation opens a door onto a further constellation of hypothetical historical tableaux'

First, the plan expresses implicitly the 'patron's share' in the conception of the church as it reveals explicitly the 'master mason's share' in devising geometrical operations that brought the design into architectural reality. Just as Suger's direction to 'harmonize the new with the old' may have set the design of twelfthcentury Saint-Denis in motion, Urban IV might have hoped aloud that his chapel's geometry would reflect that of other divinely inspired structures: the 36 Romanfoot dimension of the crossing, in addition to the square of six, is also one-fourth of 144, a dimension used, as in the Palatine Chapel at Aachen, as a signifier for the Celestial Jerusalem. Second, if the 36-foot crossing was deliberately chosen, then the pontiff himself and his mason may have had conversations that ranged over the streets of Troyes, craft rules of design, historical models for the project, and the theology of numbers. Time-consuming correspondence between Italy and Champagne or communication through agents and intermediaries seems far less plausible than a face-to-face interview in Viterbo. Third, the designer reasonably would work out the connection between the two geometric systems-the outer envelope based on specific physical parameters, the interior developed from a dimension chosen, at least in part, because of its symbolic value- in sketches and drawings.

The 'symbolic generator' is a theoretical house of cards built of fictionalized conversations, imagined decisions, and plausible geometry. Nevertheless, in my opinion, it offers the most satisfying story of the design of Saint-Urbain for it generates an architectural narrative that is active, complex, and human. As Simon Schama writes, In its original Greek sense the word "historia" meant an inquiry ... But to have an inquiry, whether into the construction of a legend or the execution of a crime, is surely to require the telling of stories. And so the asking of questions and the relating of narratives need not, I think, be mutually exclusive forms of historical representation. And if in the end we must be satisfied with nothing more than broken lines of communication to the past ... that perhaps is well enough to be going on with."