All this time the papacy was in a very sad condition. Popes were set up and put down continually, and some of them were put to death by their enemies. The body of one pope named Formosus, after it had been some years in the grave, was taken up by order of one of his successors (Stephen VI.), was dressed out in the full robes of office, and placed in the papal chair; and then the dead pope was tried and condemned for some offence against the laws of the Church. It was declared that the clergy whom he had ordained were not to be reckoned as clergy; his corpse was stripped of the papal robes; the fingers which he had been accustomed to raise in blessing were cut off; and the body, after having been dragged about the city, was thrown into the Tiber (A.D. 896). Otho the Great, who has been mentioned as emperor, turned out a young pope, John XII., who was charged with all sorts of bad conduct (A.D. 963); and that emperor's grandson, Otho III., put in two popes, one after another (A.D. 996, 999). The second of these popes was a very learned and clever Frenchman, named Gerbert, who as pope took the name of Sylvester II. He had studied under the Arabs in Spain (for in some kinds of learning the Arabs were then far beyond the Christians); and it was he who first taught Christians to use the Arabic figures (such as 1, 2, and 3) instead of the Roman letters or figures (such as I., II., and III.). He also made a famous clock; and on account of his skill in such things people supposed him to be a sorcerer, and told strange stories about him. Thus it is said that he made a brazen head, which answered "Yes" and "No" to questions. Gerbert asked his head where he should die, and supposed from the answer that it was to be in the city of Jerusalem. But one day as he was at service in one of the Roman churches which is called "Holy Cross in Jerusalem," he was taken very ill; and then he understood that that church was the Jerusalem in which he was to die. We need not believe such stories; but yet it is well to know about them, because they show what people were disposed to believe in the time when the stories were made.