One of the most distinguished members of the Chora was the historian Nicephorus Gregoras, who learned to know the monastery through his friendship with Theodore Metochites. The two men met first when Nicephorus came from his native town Heraclea on the Black Sea to Constantinople, a youth eager to acquire the knowledge that flourished in the capital. Being specially interested in the science of astronomy, the student placed himself under the instruction of Theodore, then the greatest authority on the subject, and won the esteem and confidence of his master to a degree that ripened into the warmest friendship and the most unreserved intellectual intercourse. In his turn, Nicephorus Gregoras became the instructor of the children of the grand logothetes, and was treated as a member of the family. He was also associated with the restoration of the Chora, attending particularly to the collection of the costly materials required for the embellishment of the church. Thus the monastery became his home from youth to old age, and after Theodore's death was entrusted to his care.[532] During the fierce controversy which raged around the question whether the light beheld at the Transfiguration formed part of the divine essence, and could be seen again after prolonged fasting and gazing upon one's navel, as the monks of Mount Athos and their supporters maintained, Nicephorus Gregoras, who rejected that idea, retired from public life to defend what he deemed the cause of truth more effectively. But to contend with a master of legions is ever an unequal struggle. The Emperor John Cantacuzene, taking the side of the monks, condemned their opponent to silence in the Chora, and there for some three years Nicephorus Gregoras discovered how scenes of happiness can be turned into a veritable hell by imperial disfavour and theological odium. Notwithstanding his age, his physical infirmities, his services to the monastery, his intellectual eminence, he was treated by the fraternity in a manner so inhuman that he would have preferred to be exposed on the mountains to wild beasts. He was obliged to fetch water for himself from the monastery well, and when, on one occasion, he was laid up for several days by an injury to his foot, none of the brothers ever thought of bringing him water. In winter he was allowed no fire, and he had often to wait till the frozen water in his cell was melted by the sun before he could wash or drink. The vision of the light of the Transfiguration did not transfigure the character of its beholders.