"I Ragionamenti"-Visualizing St. Peter's

Thirteen architectural drawings by four architects-Bramante, Baldassare Peruzzi, Giuliano da Sangallo, and Antonio da Sangallo the Younger-all dating from the period between early 1505 to 18 April 1506, all except one in the Gabinetto dei Disegni e Stampe of the Uffizi, and all connected with the earliest proposals for the new St. Peter's, are examined to establish their authorship and date and the exact sequence in which they were executed. Beyond that, the chronological alignment of the drawings enables us to follow the process of visualizing and creating a building of an unprecedented type and an extraordinary scale. The ground plans of several small-scale prototypes-such as the Audience Hall of the Piazza d'Oro at Hadrian's Villa, the Oratorio of Santa Croce (a tiny 2nd- or 5th-century structure that stood near the Lateran Baptistery until the end of the 16th century), and the 9th-century San Satiro in Milan-are combined with elements of larger-scale prototypes such as San Lorenzo in Milan and the cathedrals of Milan, Pavia, and Florence in the search for a plan and elevation that are both spacious and structurally sound, that sum up both Roman architectural achievement and the heightened unities of Renaissance church design. The main concern in most of these drawings is the delineation of the crossing, the baldacchino formed by the great piers and the dome they support, protecting the tomb of St. Peter and the altar of the Early Christian church. Although in nearly every drawing some attention is paid to the outer perimeters of the building and its internal spatial divisions, many of those decisions are left in suspense, particularly the question of whether the building is to be centralized or longitudinal. Bramante's main concern was to establish the scale of the crossing, the size and shape of the piers and their distance from each other. This nucleus, constructed up through the pendentive level during his lifetime, set the scale for everything that was to follow. In the absence of a definitive plan attributable to the Bramante/Peruzzi team, the pier designs of Uff. 529 A verso and of f. 1466 verso of the Rothschild drawing book, and the interior of the crossing as it appears in the perspective drawing Uff. 2 A, are the best evidence of Bramante's permanent contribution. The drawings considered here trace the experiments with shape and scale that led to the establishment of these elements.