Upon entering the basilica of San Lorenzo in Florence one is immediately impressed by the nave arcades, those rhythmic, monumental assemblages of columns, entablature blocks and arches that in the first half of the fifteenth century established a benchmark of elegance and refinement for all subsequent architecture of the Renaissance [1]. Cool, orderly and restful yet, like springs coiled in compression, full of energy, the nave arcades are works of tremendous artistic power. By functioning so strongly as complete compositions, the nave arcades suppress the individuality of their component parts: viewed from ground level, the repeated bays all appear to be identical, even though when viewed up close the capitals and other carved details betray notably uneven levels of quality in both design and execution. This variation in quality constitutes a rich and largely untapped source of evidence pertaining to the construction history and original meaning of this pivotal work in the history of architecture.