Gerbert of Aurillac (ca. 955-1003)

Gerbert was born somewhere in the mountainous region of Auvergne, in central France. Since neither his place of birth nor his parents were recorded, it seems likely that he was of low birth. Sometime about 963, he entered the monastery of St. Gerald at Aurillac. This is the monastery that Gerald the Good had established near his castle just before his death some sixty years earlier, and where he was buried. It was, like Cluny, a rather strict Benedictine monastery and was independent of any local control, being subject only to the pope.

Here he studied his Latin grammar under a teacher by the name of Raymond, for whom he held a special affection for the rest of his life. Of course, by this time, “grammar” had come to stand for the verbal skills included in the trivium — grammar, logic, and rhetoric. In 967, Count Borrell of Barcelona visited the monastery, and the abbot asked the count to take Gerbert back to Spain with him so that the lad could study mathematics there. It would seem that Gerbert had proven to be an apt pupil, and his abbot wanted to see him go on to the study of the quadrivium — arithmetic, geometry, music, and astronomy. Borrell agreed and put the lad in the care of the bishop of Vic, where there was a cathedral school. Catalunya, in which both Barcelona and Vic were located, was a frontier territory, and there was considerable communication between Catalunya and the Muslims of al-Andalus to the south. Al-Andalus was much more advanced that Christian Europe. While the greatest library in Christian Europe boasted less than a thousand volumes, the library in the Muslim capital of Cordoba held over four hundred thousand. Catalunya benefitted from the proximity of the cultured Muslims, and the libraries of the cathedral of Vic and the nearby monastery of Ripoll were among the largest and best equipped in Europe.

The proximity of the Muslims meant more than that in the matter of the subjects of the quadrivium, however. The Muslims had fallen heir to both Greek and Persian science in their initial expansion and had translated many classics into Arabic. At the same time, Arabic traders and travelers were in contact with India and China and had absorbed many of their advances. Muslim “scientists” were highly regarded, and perhaps nowhere in Islam as much as in al-Andalus. Muslim astronomy was the most advanced in the world, and Muslim astronomers proficient in using the astrolabe had done much to map the skies. Although the names of modern planets and constellations are Latin, the names of most major stars — Altair, Deneb, Rigel, Sirius, Fomalhaut, Aldeberan, Betelgeuse — are Arabic as are many of the other terms of astronomy, such as azimuth, almagest, almanac, and the Zodiac. The Arabs were even further advanced in the realm of arithmetic. They had adopted the concept of zero from the Indians and used a positional numeric system much like the modern system — in fact, our numerals are based on the Arabic notation. They had also borrowed the abacus from the Chinese and were proficient in its use. They had gone beyond arithmetic and had established algebra, were investigating prime numbers and coordinate equations. Their study of proportions made it possible for them to approach music in a quite precise manner, distinguishing accurately between notes, developing theories of harmonies and discords, and constructing musical instruments with quite accurate tuning. The cathedral school of Vic was able to offer Gerbert much of this knowledge, and Gerbert took full advantage of the opportunity.

As a matter of fact, his knowledge and abilities were so great that some of his contemporaries could not explain them except by assuming that he was ether a magician or had made a pact with the devil. It was in this fashion that the Gerbert of legend arose.

Gerbert had travelled to Spain, where he became the apprentice of a Muslim magician of wondrous powers. Gerbert came to realize that all of the magician’s powers came from the spells that were contained in a book that he kept under lock and key. At the same time, the magician began to suspect that Gerbert wanted to steal his secrets and take them away with him, and so began to watch him very closely and to hide the key to the chest in which he kept his book. The magician had a beautiful daughter, and Gerbert seduced her with the promise of taking her away with him and marrying her. The duped girl helped Gerbert put a drug in her father’s evening wine and, when he had fallen into a stupor, got the key from where he had hidden it, opened the chest, and gave Gerbert the book.

Gerbert immediately fled, leaving the girl behind. When the magician awoke and saw what had happened, he got his horse, which could run faster than the wind, and his dog, which could track anything or anyone over or under both ground and water. As he came to the bridge at Martorell, Gerbert heard the magician riding after him and knew that he had to escape the magician’s dog. He quickly climbed over the side of the bridge and hung by his hands beneath it. Since he was neither above or below either the earth or water, the dog lost his scent, and the baffled magician finally returned home, leaving Gerbert with the book of spells.

Some say that he prayed to Satan to save him from the magician, and that Satan wafted him away beyond the sea. In order to get home, Gerbert agreed to give his soul to Satan, and Satan, in turn, promised to give him powers even greater than those contained in the book of spells. The proof that this story is the correct one is found in the fact that Gerbert kept a human head with him and would put the head on his desk and converse with it through the night, learning many secrets and about the future from it.

In 969, Count Borrell and the bishop of Vic made a pilgrimage to Rome, taking young Gerbert with them. He met and impressed Pope John XIII (965-971) and the emperor Otto I (962-973), who was visiting there also. The pope persuaded Otto to take Gerbert on as tutor for his young son, who was to become Otto II (973-983). After some years at this task, Otto gave Gerbert leave to go to study advanced logic at the outstanding cathedral school of Reims.

He made quite a name for himself at Reims. He set himself to the task of building an organ with constant pressure supplied by water power. There had been organs before, but their air pressure had been generated by the organist pumping with his feet of an assistant pumping a large bellows. This one not only gave an extended steady level of sound, but its pipes were matched mathematically so that its harmonics were superior to anything heard in the West before. Gerbert had also mastered arabic numerals and so could do calculations in his head that were extremely difficult for anyone thinking in terms of Roman numerals. He continued to study the abacus, and even constructed a giant one. He marked out the floor of the nave of the cathedral of Reims like an abacus and made a number of large disks to take the place of the abacus beads. He gathered some sixty-four members of the cathedral school to help him, gave them sticks to push the disks, and sat in the organ loft from where he could see the entire floor. He would call out instructions, and his assistants would move the disks like a great game of shuffleboard. He was able in this way to deal with numbers both larger and smaller than had ever before been possible. He then wrote a book on the abacus that became standard in the new cathedral schools that were arising and revolutionized the study of mathematics in the West.

He was invited to Ravenna to engage in a debate and, while there, renewed his acquaintance with his old pupil Otto. Otto was quite impressed by him and, when he became Holy Roman Emperor in 983, he made Gerbert the abbot of the famous monastery of Bobbio and also appointed him as count of the district in which it was located. Bobbio had been founded by St. Columban and had one of the greatest libraries in Western Europe. It was close to Genoa and had grown wealthy from the trade and commerce that were beginning to enrich all of northern Italy, but it had fallen on hard times. Incompetent abbots had depleted its treasury, local nobles had seized its lands, and its monks had fallen into a dissolute way of life. Gerbert undertook to remedy these matters, but did not get very far.

Otto died the next year, however, and Gerbert lost his patron and protector. Nevertheless, his reputation was so great that he was invited to return as the master of the cathedral school of Reims and secretary to the archbishop. He became deeply involved in the political struggles of the times. Basically, there was a struggle between the Saxon dynasty of Germany, represented by the young Otto III and the Carolingian claimants to the throne of France. When Lothair of France attempted to take Lorraine from Otto III in 985, Gerbert and his archbishop opposed him by supporting Hugh Capet, the count of Paris, as the real ruler of France. By 987, both Lothair and his son had died, and the Carolingian heir was Charles, duke of Lower Lorraine. Charles asked Gerbert and his archbishop for their support, but both used their influence on behalf of Hugh. Hugh was elected king of France, and the Carolingian line of kings came to an end.

The archbishop died in 989, and Gerbert expected to succeed him. Hugh appointed Arnulf, a bastard son of the late King Lothair instead. Archbishop Arnulf was conspiring with the Carolingian Duke Charles, however, and turned over Reims to him in 989. The city was devastated, Gerbert’s possessions seized, and most of his friends imprisoned or driven off. He finally managed to escape his post as the archbishop’s secretary and fled to the court of King Hugh. In 991, Hugh finally had proof of Archbishop Arnulf’s treason, deposed him, and appointed Gerbert in his place.

From 991-997, struggled to hold on to his archbishopric, but eventually lost out. Hugh Capet died in 996, and Gerbert clashed with his successor, Robert II (996-1031), when Gerbert declared Robert’s marriage to his cousin Bertha illegal. Then, in 997, Pope Gregory V (996-998) stripped Gerbert of his episcopal functions. Gerbert fled to the court of Otto II, where he was welcomed and given a small estate. After a short period of relaxation, Gerbert was called to become the teacher and advisor of Otto III, then only seventeen years old. Otto was in Ravenna, the southern capital of the Holy Roman Emperors at the time. When Pope Gregory V died in 999, Otto decided to wrest control of the papacy from local politics and did so by appointing Gerbert pope. Gerbert took the name Sylvester II. Sylvester I (314-335) having been the advisor of the emperor Constantine.

Within short order, the Roman populace rebelled against a foreign pope, and both Otto and Gerbert were forced to flee to Ravenna. Otto led two unsuccessful expeditions to regain control of the city, and, on a third, in 1002, he died in his twenty-first year.

The legend says that Gerbert had built a mechanical head that would answer any questions that could be answered with either “yes” or “no.” It had said “yes” when he asked it if he would become pope, so he asked it if he would die before he had said mass in Jerusalem. The head said “no,” and Gerbert decided that he would never go to Jerusalem. In the course of his duties, he said mass in one of the smaller churches in Rome and afterwards discovered that it was the church of St. Mary of Jerusalem, commonly called by the people simply “Jerusalem.” He became sick shortly after, and called for his followers. In his final delirium, he asked the cardinals to cut his body into pieces and throw them into the cesspools and garbage dumps of the city, saying that, while his body might belong to Satan, he had never consented in his mind to the oath that the devil had made him swear.

Dr. Lynn H. Nelson
Professor Emeritus, Medieval History
University of Kansas
1 January 2001

Silvestri II,… Aimoini, floriacensis monachi, sancti Abbonis, abbatis floriacensis, Thietmari, merseburgensis episcopi, opera omnia. Accedunt Joannis XVIII, Sergii IV, Benedicti VIII,… Epistolae et diplomata. Intermiscentur Arnulfi remensis, Aelfrici cantuariensis,… Notgeri leodiensis, Henrici parmensis, Brunonis lingonensis, Arnoldi halberstatensis,… Gosperti, abbatis tegernseensis, Alberti, abbatis miciacensis, Herigeri abbatis lobiensis, Constantini, S. Symphoriani abbatis, Tietpaldi, tegernseensis monachi, Benedicti, monachi S. Andreae, Purchardi, monachi Angiae Divitis, Roriconis, monachi moissiacensis, Joannis, Diaconi veneti, Bridferti, ramesiensis monachi, scripta quae exstant, accurante J.-P. Migne,…
Source: Bibliothèque nationale de France

Gerbert un pape philosophe : d’après l’histoire et d’après la légende / par F. Picavet,…
Source: Bibliothèque nationale de France

Lettres de Gerbert (983-997) / publiées, avec une introd. et des notes, par Julien Havet
Source: Bibliothèque nationale de France

Études critiques sur divers textes des Xe et XIe siècles. Bulle du pape Sergius IV. Lettres de Gerbert / par Jules Lair,…
Source: Bibliothèque nationale de France

Oeuvres de Gerbert, pape sous le nom de Sylvestre II… / précédées de sa biographie, suivies de notes critiques & historiques par A. Olleris,…
Source: Bibliothèque nationale de France

Schultess. Papst Silvester II. (Gerbert) als Lehrer und Staatsmann. 1891.

Picavet. Gerbert, un pape philosophe d’après l’historie et d’après la légende. 1897.

Werner. Gerbert von Aurillac : die kirche und wissenschaft seiner zeit, neue ausgabe. 1881.