There is no other way left to show to Florence that he has always been true to her.
And at the moment of his death, all who spied on him, distrusted and condemned him, are convinced of his fidelity.

Even before he dies, his devotion to his ideal aim, his absolute unselfishness, have won over and ennobled all the self-interested characters which surround him--Puccio, the general who is jealous of him; Domizia, the woman who desires to use him as an instrument of her hate to Florence; even Braccio, the Macchiavellian Florentine who thinks his success must be dangerous to the state.

Luria conquers them all.

It is the triumph of self-forgetfulness.

And the real aim of the play is not dramatic.