The religion of Christ was lost, man had become a stranger to his own soul--celestial warnings, signs of the Judgment Day, daemonic temptations, surrounded him, as far as he paid heed to anything super-sensuous on all sides. The French chronicler, Radulf Glaber (about A.D. 1000), might have been writing a satire on antiquity when he warned his contemporaries of the demons lurking everywhere, but more especially dwelling in trees and fountains. Of a learned man who was studying the classic poets, he said: "This man, confused by the magic of evil spirits, had the impudence to propound doctrines contradictory to our holy faith. In his opinion everything the ancient poets had maintained was true. Peter, the bishop of the town, condemned him as a heretic. At that time there were many men in Italy believing this false doctrine; they perished by the sword or at the stake." We have a letter, written at the same time by Gerbert, who later on became Pope Sylvester II., to a friend, beseeching him to obtain for him manuscripts of the Latin philosophers and poets. He wrote textbooks of astronomy, geometry and medicine, and introduced the Arabic numbers and the decimal system into Europe. In consequence he, too, was accused of magic and intercourse with Arabian pagans. A chronicler relates that he sold his soul to the devil and became pope through the devil's agency; and that, when he was on the point of death, he ordered his body to be cut to pieces so that the devil should not carry it away.