Plans for New St Peter's in Rome

Beginning in 1505, at first in competition with two other architects, Giuliano da Sangallo and Fra Giocondo, Bramante planned the new Basilica of St. Peter in Rome - his greatest work and one of the most ambitious building projects up to that date in the history of humankind. The first stone was placed on April 18, 1506. The project's site had to be cleared first of the old, crumbling Basilica of Constantine. Bramante's part in its demolition earned him the nicknames of "Maestro Ruinante" or "Master Wrecker." At the time of his death the new construction had scarcely begun to take shape.

Bramante's design, which was preferred to proposals submitted by Giuliano da Sangallo and Fra Giocondo, is represented on Caradosso's foundation medal (1506; e.g. National Gallery of Art, Washington), and the same design, apart from some minor deviations of detail, is recorded in a half-plan drawing known as the Parchment Plan (1A, Galleria degli Uffizi, Florence). The layout seems to have grown out of the ideas he had considered at Pavia Cathedral and Santa Maria delle Grazie, namely a domed Greek cross inscribed within a square and with apses on the main axes. It is here further elaborated with four subsidiary domes on the diagonals, where the Greek-cross arrangement is repeated on a smaller scale, and with four corner towers. The centre of the design corresponds fittingly with the revered tomb of St Peter, and the multi-domed layout recalls that of earlier sepulchral churches, such as San Marco, Venice. The arrangement of the crossing is a major innovation in church design, with diagonal chamfers to the massive crossing piers giving the dome a much greater diameter than the width of the arms.

In its enormous scale, Bramante's design for St Peter's was quite without precedent for a post-medieval church and relied heavily on ancient Roman bath complexes, which seem to have inspired a wholly new approach to spatial planning. Whereas during the 15th century internal spaces were conceived as a product of designing walls, in St Peter's the walls were a product of designing spaces. Through this new approach, greatly aided by Bramante's revival of Roman brick-and-concrete construction, the massive vault-bearing walls took up the residual areas between neighbouring spaces and were hollowed out in a multitude of alcoves, arches and niches.

Bramante's design for the dome, with its colonnaded drum resembling a circular temple and its crowning lantern, is known also from a plate in Serlio (Book III). In shape (hemispherical on the inside, stepped and dishlike on the outside) as well as in size, the design abandoned contemporary practice and was closely modelled instead on the Pantheon. The much greater overall size of St Peter's, however, compared with the Pantheon, was no doubt regarded as emblematic of the triumph of Christianity over ancient paganism and of the authority of papal rule.

The Parchment Plan design was, nevertheless, just one of many alternatives considered even as construction progressed. No decision seems to have been made by Bramante's death, however, even though the crossing had been substantially completed up to the height of the drum, with piers and attached Corinthian pilasters using capitals copied from those inside the Pantheon.

The picture shows Bramante's plan for the dome. You can also view Bramante's design of the ground plan for St Peter's.