Sentence:  Ne he his mouth would open unto wight, / Untill that Guyon selfe unto him spake, / And called Brigadore, (so was he hight,) / Whose voice so soone as he did <WSD>undertake</WSD>, / Eftsoones he stood as still as any stake, 
Meaning of the word marked with <WSD> tags:  To have knowledge of; to hear.