Sentence:  It was by Merlyns auyse said the knyghte / As for hym sayd kynge Carados / I wylle encountre with kynge bors / and ye wil rescowe me whan <WSD>myster</WSD> is / go on said they al / we wil do all that we may 
Meaning of the word marked with <WSD> tags:  Necessity; the necessary time.