This was not, however, quite the only reason of my departure; there was something else, which I do not wish to communicate; enough that it made me think that, if I stayed in Rome, that city would be my tomb before it was the Pope's.

And this was the cause of my sudden departure.
"Now you write to me at the Pope's instance.

So I beg you to read him this letter, and inform his Holiness that I am even more than ever disposed to carry out the work." Further details may be added from subsequent letters of Michelangelo.
Writing in January 1524 to his friend Giovanni Francesco Fattucci, he says: "When I had finished paying for the transport of these marbles, and all the money was spent, I furnished the house I had upon the Piazza di S.Pietro with beds and utensils at my own expense, trusting to the commission of the tomb, and sent for workmen from Florence, who are still alive, and paid them in advance out of my own purse.
Meanwhile Pope Julius changed his mind about the tomb, and would not have it made.

Not knowing this, I applied to him for money, and was expelled from the chamber.

Enraged at such an insult, I left Rome on the moment.