Pope. Gerbert is important both as a scholar and as a Churchman. It appears that in the school at Reims he was the first master in Europe to use a substantial part of the logical works of Aristotle and Boethius as a practical system of education, and he wrote extensively on mathematics. He became Abp. of Reims in 991, of Ravenna in 998, and Pope in 999. He owed these promotions to the Emp. Otto III, and his choice of name was in conscious imitation of Sylvester I, who had long been regarded as the pattern of Papal co-operation with the Emperor. As Pope, he opposed simony and upheld clerical celibacy, and did much to strengthen the Church in E. Europe. He established archbishoprics in Gniezno (Poland) and Esztergom (Hungary) and recognized St Stephen of Hungary as king.