SYLVESTER, the name of two popes, and of a third who was an anti-pope. The pon tificate of the first immediately succeeded that of Melchiades in 314, and is memorable for the great council of Niema, in which the heresy of Arius was condemned. Sylvester himself did not attend the council, but sent two priests—Vitus and Vicentius—to take his place. His name is also celebrated in connection with the so-called donation of Con stantine to the Roman church, the .spuriousness of which (although no doubt had been raised regarding it during many centuries) has long been admitted by critics. He died. in 335. Sylvester II., one of the most learned of the medheval popes, originally called Gerbert, was b. at Aurillac, in Auvergne, early in the 10th century. He was educated in the monastery of his native village; but went early to Spain, where he learned mathe matics, and afterward to Rome. He was appointed abbot of the monastery of Bobbio, where he taught with much distinction and success. At a later period he went to Ger many as preceptor of the young prince Otho, afterward Otho II.; and ultimately became
secretary to the archbishop of Rheims, and director of the cathedral school, which became eminent under his care. The archbishop having been deposed, Sylvester was elected the archbishopric; but he was afterward set aside, the deposition of his predecessor having been declared invalid. In the year 998, however, he was appointed archbishop of Ravenna, whence he was called to the pontifical throne, in the following year, under the name of Sylvester II. He was a man of rare acquirements for his age. He was as adept in mathematics, and in practical mechanics and astronomy, in which department his attainments acquired for him among his contemporaries the evil reputation of a magi cian. He is also believed to have been acquainted with Greek, and perhaps with Arabic._ Of all his works, which were numerous, his letters (printed by Du Chesne in the Histori ans of France) have attracted most notice from their bearing on the history of an obscure period.