In some cases this change is strictly justifiable; as, when a person is addressed in a different style. For example, in Thomson’s Tancred and Sigismunda, when Siffredi discloses to Tancred that he is the king, he says,

Forgive me, sir! this trial of your heart.

For the respectful appellation sir demands the more colloquial term of address, but he immediately adds with animation,

Thou! thou! art he!

And so in Tancred’s subsequent speech to Siffredi, he first says,

I think, my lord! you said the king intrusted
To you his will!—

but soon after adds, in a more impassioned tone,

On this alone I will not bear dispute,
Not even from thee, Siffredi!

The same distinction will, in general, be found in the speeches of Sigismunda to Tancred.[352]