Michelangelo had come to Rome under San Gallo's influence, and Bramante had just succeeded in winning the commission to rebuild S.Peter's over his rival's head.

It was important for him to break up San Gallo's party, among whom the sincere and uncompromising Michelangelo threatened to be very formidable.

The jealousy which he felt for the man was envenomed by a fear lest he should speak the truth about his own dishonesty.

To discredit Michelangelo with the Pope, and, if possible, to drive him out of Rome, was therefore Bramante's interest: more particularly as his own nephew, Raffaello da Urbino, had now made up his mind to join him there.

We shall see that he succeeded in expelling both San Gallo and Buonarroti during the course of 1506, and that in their absence he reigned, together with Raffaello, almost alone in the art-circles of the Eternal City.
I see no reason, therefore, to discredit the story told by Condivi and Vasari regarding the Pope's growing want of interest in his tomb.
Michelangelo himself, writing from Rome in 1542, thirty-six years after these events, says that "all the dissensions between Pope Julius and me arose from the envy of Bramante and Raffaello da Urbino, and this was the cause of my not finishing the tomb in his lifetime.