The Prologue was a conventional requirement for all plays. This one was delivered by the sixty-five-year-old Betterton, the grand old man of the Restoration stage. Congreve did not keep the promises he made in this prologue:
He swears he'll not resent one hissed-off scene,
Nor, like those peevish wits, his play maintain,
Who, to assert their sense, your taste arraign.
The dedicatory letter indicates that he did arraign the taste of his audience because it did not approve his play (although his scenes were not hissed).
His statement about what is in his play has more value: "some plot," "some new thought," "some humor too," but "no farce," the absence of which, he adds, ironically, would presumably be a fault. The fact that he describes his play as having no farce indicates that he planned the Wilfull-Witwoud scenes and the Lady Wishfort scenes as less broadly burlesqued than some of his contemporaries might have wished.
The statements that there is no satire because the town is so reformed and that there are surely no knaves or fools in his audience are, of course, ironic.