No reader can doubt that he has done so.

Nor is the reader ever struck with the affectation of an assumed dialect.

The words come as though they had been written naturally,--though not natural to the middle of the nineteenth century.

It was a tour de force; and successful as such a tour de force so seldom is.

But though Thackeray was successful in adopting the tone he wished to assume, he never quite succeeded, as far as my ear can judge, in altogether dropping it again.
And yet it has to be remembered that though _Esmond_ deals with the times of Queen Anne, and "copies the language" of the time, as Thackeray himself says in the dedication, the story is not supposed to have been written till the reign of George II.