Sentence:  Jacques LeGoff remarks, <WSD>'Hagiography</WSD> tells us much about the mental infrastructure [of the middle ages]: the interpenetration between the tangible world and the supernatural world, the common nature of the corporeal and psychic, are the conditions which make miracles and related phenomena possible. 
Meaning of the word marked with <WSD> tags:  The study of saints and the documentation of their lives.