He continued to the end of his days in close friendship with Cavalieri, who helped to nurse him during his last illness, who took charge of his effects after his death, and who carried on the architectural work he had begun at the Capitol.
Their friendship seems to have been uninterrupted by any disagreement, except on one occasion when Michelangelo gave way to his suspicious irritability, quite at the close of his long life.

This drew forth from Cavalieri the following manly and touching letter:-- "Very magnificent, my Lord,--I have noticed during several days past that you have some grievance--what, I do not know--against me.
Yesterday I became certain of it when I went to your house.

As I cannot imagine the cause, I have thought it best to write this, in order that, if you like, you may inform me.

I am more than positive that I never offended you.

But you lend easy credence to those whom perhaps you ought least to trust; and some one has possibly told you some lie, for fear I should one day reveal the many knaveries done under your name, the which do you little honour; and if you desire to know about them, you shall.