Iwis, Ywis, i-wis′, adv. certainly—sometimes ignorantly written I wis, as if 'I know.'

The Child of Elle he hyed him thence, Ywis he stoode not stille,10 And soone he mette faire Emmelines page Come climbing up the hille.

It would be equally impossible, I believe, to find a real sunset in Chaucer; Criseyde’s “Ywis, it will be night as fast,” is quite a characteristic epitaph for the dying day.

‘I grant, ywis,’ quoth he; ‘but I must think Upon some honest thing, the while I drink.’

Her sweren zounds which be Gog's wounds, By bricht Marie and Gis, By sweit Sanct Ann and holie Tan And by Bryde's bell, ywis.