Definition of "certes"

[F]or certes, ſayes he, / I haue already choſen my officer, and what was he? / Forſooth, a great Arithmeticion, [...]

c. 1603–1604 (date written), William Shakespeare, The Tragœdy of Othello, the Moore of Venice. […] (First Quarto), London: […] N[icholas] O[kes] for Thomas Walkley, […], published 1622, [Act I, scene i], page 1

This was very unpleasant, at least to myself; though, certes, it did not prey upon the minds of the others.

1845, Herman Melville, Omoo

Here, certes, was no lost soul, but one who had gone joyfully to meet her Lord.

1902, John Buchan, The Outgoing of the Tide