"Plight me thy trouthe heere in myn hand," quod she,
"The nexte thyng that I requere thee,
Thou shalt it do, if it lye in thy myght,
And I wol telle it yow er it be nyght."
"Have heer my trouthe," quod the knyght, "I grante."
– Geoffrey Chaucer
The Canterbury Tales, The Wife of Bath’s Tale. The Knight tells the old woman that he is as good as dead unless he can say what it is that women most desire. She says she will reveal it to him before it is night, if he gives his word that the next thing she requires of him he will do it. So he pledges his word.