Sentence:  If, mindless of <WSD>palliating</WSD> circumstances, we are bound to regard the death of the Master-at-arms as the prisoner's deed, then does that deed constitute a capital crime whereof the penalty is a mortal one? 
Meaning of the word marked with <WSD> tags:  To lessen the severity of; to extenuate, moderate, qualify. (17th-18th c.)