the cross, supported a broad shallow dome, modelled upon that of the Pantheon.  Similar domes of lesser dimensions crowned the out-buildings.  He began by erecting the piers which were intended to support the central dome; but working hastily and without due regard to solid strength, Bramante made these piers too weak to sustain the ponderous mass they had to carry.  How he would have rectified this error cannot be conjectured.  Death cut his labours short in 1514, and only a small portion of his work remains embedded at the present day within the mightier masses raised beneath Buonarroti’s cupola.

Leo X. commissioned Raffaello da Urbino to continue his kinsman’s work, and appointed Antonio da Sangallo to assist him in the month of January 1517.  Whether it was judged impossible to carry out Bramante’s project of the central dome, or for some other reason unknown to us, Raffaello altered the plan so essentially as to design a basilica upon the conventional ground-plan of such churches.  He abandoned the Greek cross, and adopted the Latin form by adding an elongated nave.  The central piers were left in their places; the three terminal apses of the choir and transepts were strengthened, simplified, reduced to commonplace.  Bramante’s ground-plan is lucid, luminous, and exquisitely ordered in its intricacy.  The true creation of a builder-poet’s brain, it illustrates Leo Battista Alberti’s definition of the charm of architecture, tutta quella musica, that melody and music of a graceful edifice.  We are able to understand what Michelangelo meant when he remarked that all subsequent designers, by departing from it, had gone wrong.  Raffaello’s plan, if carried out, would have been monotonous and tame inside and out.

After the death of Raffaello in 1520, Baldassare Peruzzi was appointed to be Sangallo’s colleague.  This genial architect, in whose style all the graces were combined with dignity and strength, prepared a new design at Leo’s request.  Vasari, referring to this period of Peruzzi’s life, says:  “The Pope, thinking Bramante’s scheme too large and not likely to be in keeping, obtained a new model from Baldassare; magnificent and truly full of fine invention, also so wisely constructed that certain portions have been adopted by subsequent builders.”  He reverted to Bramante’s main conception of the Greek cross, but altered the details in so many important points, both by thickening the piers and walls, and also by complicating the internal disposition of the chapels, that the effect would have been quite different.  The ground-plan, which is all I know of Peruzzi’s project, has always seemed to me by far the most beautiful and interesting of those laid down for S. Peter’s.  It is richer, more imaginative and suggestive, than Bramante’s.  The style of Bramante, in spite of its serene simplicity, had something which might be described as shallow clearness.  In comparison with Peruzzi’s style, it is what Gluck’s melody is to Mozart’s.