But Bramante manifested his real powers in his project for the great church of St. Peter, his capital work, which, however, was never carried to completion. It is well known how Pope Julius II had conceived the idea of erecting a vast tomb for himself, and had employed Michael Angelo to prepare the design. We are told by Vasari[38] that the project submitted by this great artist so pleased the Pope that he determined to rebuild the church of St. Peter in order to make it more worthy to enshrine so magnificent a monument. Under Pope Nicholas V, half a century before, the grand old basilica, that had stood since the time of Constantine, had been partially demolished, and a new edifice on a larger scale begun by the Florentine architect, Rossellino. This work had not progressed very far when it was suspended on the death of this Pope, and operations had not been resumed until now, when Pope Julius resolved to demolish Rossellino’s beginning along with what remained of the old structure, and to make a fresh start with a still grander scheme, which was prepared by Bramante, who began the new work in the year 1506. There is much uncertainty as to the exact nature of Bramante’s design for the building as a whole. No authentic drawings embodying the definitive project are known to exist, and in the monument itself Bramante did not go far enough to show his whole intention. Even what he actually did cannot be wholly made out with clearness, because so many other hands were employed after his death. The exact form of his plan is uncertain, though there appears little question that it was to be in the form of the Greek cross with towers set in the external angles, and it is certain that a vast dome was to rise over the crossing.[39] The work, though considerably advanced, was not nearly completed when, in the year 1514, the master died. He appears to have built the great piers for the support of the dome, with their connecting arches and pendentives, but not to have begun the dome itself. [Illustration: FIG. 23.--Bramante’s dome for St. Peter’s, from Serlio.] The scheme was to be a colossal one, and the dome was to be its main feature. We may presume that Bramante naturally shared the universal feeling of admiration for Brunelleschi’s dome, and that he wished to rival its imposing character. But his ardent and intelligent study of the monuments of Roman antiquity had given him a better appreciation of their superior structural merits, and in his project for the great dome he had sought to adhere more closely than Brunelleschi had done to the ancient principles and ancient forms.