Besides being the most distinguished statesman, Gerbert was also the most accomplished scholar of his age. His pupil Richer has left us a detailed account of his system of teaching at Reims. So far as the trivium is concerned, his text-books were Victorinus's translation of Porphyry's Isagoge, Aristotle's Categories, and Cicero's Topics with Manlius's Commentaries. From dialectics he urged his pupils to the study of rhetoric ; but, recognizing the necessity of a large vocabulary, he accustomed them to read Virgil, Statius, Terence, Juvenal, Horace, Persius and Lucan. More remarkable still were his methods of teaching the quad rivium. To assist his lectures on astronomy he constructed elabo rate globes of the terrestrial and celestial spheres, on which the course of the planets was marked ; for facilitating arithmetical and perhaps geometrical processes he constructed an abacus with 27 divisions and a thousand counters of horn. A younger con temporary speaks of his having made a wonderful clock or sun dial at Magdeburg; and we know from his letters that Gerbert was accustomed to exchange his globes for mss. of those classical authors that his own library did not contain. More extraordinary still was his knowledge of music-an accomplishment which seems to have been his earliest recommendation to Otto I. Gerbert's letters contain more than one allusion to organs which he seems to have constructed, and William of Malmesbury has preserved an account of a wonderful musical instrument still to be seen in his days at Reims. The same historian tells us that Gerbert borrowed from the Arabs (Saraceni) the abacus with ciphers. (See NU MERALS.) Perhaps Gerbert's chief claim to the remembrance of posterity is to be found in the care and expense with which he gathered together mss. of the classical writers. His love for litera ture was a passion. In the turmoil of his later life he looked back with regret to his student days, and "for all his troubles philosophy was his only cure." Everywhere-at Rome, at Treves, at Moutier-en-Der, at Gerona in Spain, at Barcelona-he had friends or agents to procure him copies of the great Latin writers for Bobbio or Reims. To the abbot of Tours he writes that he is "labouring assiduously to form a library," and "throughout Italy, Germany and Lorraine (Belgica) is spending vast sums of money in the acquisition of mss." It is noteworthy, however, that Ger bert never writes for a copy of one of the Christian fathers, his aim being, seemingly, to preserve the fragments of a fast-perish ing secular Latin literature.
So remarkable a character as that of Gerbert left its mark on the age, and fables soon began to cluster round his name. See FAUST. Towards the end of the 1 i th century Cardinal Benno, the opponent of Hildebrand, is said to have made him the first of a long line of magician popes. William of Malmesbury adds a love adventure at Cordova, a compact with the devil, the story of a speaking statue that foretold Gerbert's death at Jerusalem-a prophecy fulfilled, somewhat as in the case of Henry IV. of Eng land, by his dying in the Jerusalem church of Rome-and that imaginative story of the statue with the legend "Strike here," found its way into the Gesta Romanorum.
Gerbert's extant works may be divided into five classes. (a) A col lection of letters, some 23o in number, contained for the most part in an iith-century ms. at Leiden. Other important mss. are those of the Barberini Library at Rome (late 16th century), of Middlehill (17th century), and of St. Peter's abbey, Salzburg. With the letters may be grouped the papal decrees of Gerbert when Silvester II. (b) The Acta concilii Remensis ad Sanctum Basolum, a detailed account of the pro ceedings and discourses at the great council of St. Basle ; a shorter account of his apologetic speeches at the councils of Mouzon and Causey ; and drafts of the decrees of two or three other councils or imperial constitutions promulgated when he was archbishop of Ravenna or pope. The important works on the three above-mentioned councils are to be found in the II th-century Leiden ms. just alluded to. (c) Gerbert's theological works comprise a Sermo de informations episcoporum and a treatise entitled De corpore et sanguine Domini, both of very doubtful authenticity. (d) Of his philosophical works we only have one, Libellus de rationali et ratione uti, written at the re quest of Otto III. and preserved in an I 1 th-century ms. at Paris. (e) His mathematical works consist of a Regula de abaco computi, of which a 12th-century ms. is to be found at the Vatican ; and a Libellus de numerorum divisions (nth- and 12th-century mss. at Rome, Montpellier and Paris), dedicated to his friend and correspond ent Constantine of Fleury. A long treatise on geometry, attributed to Gerbert, is of somewhat doubtful authenticity. To these may be added a very short disquisition on the same subject addressed to Adalbold, and a similar one, on one of his own spheres, addressed to Constantine, abbot of Micy. All the writings of Gerbert are collected in the edition of A. 011eris (Clermont, 1867).