In the treatise of twenty-one chapters, which simply tells how to use the astrolabe, there is naturally no reference to judicial astrology. But in the introduction of the anonymous writer to his translation from the Arabic of a work on the astrolabe there is mention of the influence of the stars. Their “concord with all mundane creatures in all things” is regarded as established by “secret institution of divinity and by natural law” and testified to by scientists.[2806] Not only is the effect of the moon on tides adduced as usual as an example, but God is believed to have set the seal of His approval upon “this discipline,” when He made miraculous use of the stars and heavens to mark the birth and passion of His Son. The writer, however, stigmatizes as a “frivolous superstition” the doctrine of the Chaldean genethlialogi, “who account for the entire life of man by astrological reasons” and “try to explain conceptions and nativities, character, prosperity and adversity from the courses of the stars.” Something nevertheless is to be conceded to them, provided all things are recognized as under divine disposition. But their doctrine is an egg which is not to be sucked unless rid of the bad odors of error.[2807] The translator urges the importance of a knowledge of astronomy in determining the date of church festivals and canonical hours. He cites Josephus concerning Abraham’s instruction of the Egyptians in arithmetic and astronomy, but regards Ptolemy as the most illustrious of all astronomers and the astrolabe as the invention of his “divine mind.” The translator wishes his readers to understand that he is offering them nothing new but only reviving the discoveries of the past, and that he is simply presenting what he finds in the Arabic.
Question of Gerbert’s attitude toward astrology.
If Gerbert could be shown to be the translator who wrote this introduction, it would be a more valuable bit of evidence as to his attitude toward astrology than anything that we have at present. His surely genuine mathematical works, as edited by Bubnov, consist solely of a short geometry and a few of his letters in which mathematical topics, mainly the abacus, are touched upon. His contemporary and disciple, the historian Richer, tells in the well-known passage[2808] how Borellus, “the duke of Hither Spain,” took Gerbert as a youth from the monastery at Aurillac in Auvergne back with him across the Pyrenees and entrusted his education to Hatto, bishop of Vich, in the north-eastern part of the peninsula. Whether Gerbert studied Arabic or not Richer does not state. Since he is still described as adolescens when the duke and bishop take him with them to Italy and leave him there with the pope, one would infer that he probably had not engaged in the work of translation from the Arabic. Another almost contemporary writer, alluding very briefly to Gerbert, makes him visit Cordova, but is perhaps mistaken.[2809] Richer does, however, state that Berbert especially studied mathesis, a word which, as various medieval writers inform us, may mean either mathematics or divination. Apparently Richer uses it in the former sense, for later he mentions only Gerbert’s achievements in arithmetic, geometry, music, and astronomy.[2810] But Robert, king of France, 987-1031, whose teacher Gerbert had been, seems to refer to him as “that master Neptanebus” in some verses,[2811] a name which certainly suggests an astrologer, as well as an instructor of royalty, if not also a magician.
His posthumous reputation as a magician.
But Gerbert’s reputation for magic seems to start with William of Malmesbury in the first half of the twelfth century, who makes him flee by night from his monastery to Spain to study “astrology” and other arts with the Saracens, until he came to surpass Julius Firmicus in his knowledge of fate. There too, according to William of Malmesbury, “he learned what the song and flight of birds portend, to summon ghostly figures from the lower world, and whatever human curiosity has encompassed whether harmful or salutary.” William then adds some more sober facts concerning Gerbert’s mathematical achievements and associates.[2812] Michael Scot in his Introduction to Astrology in the early thirteenth century speaks of a master Gilbertus who was the best nigromancer in France and whom the demons obeyed in all that he required of them day and night because of the great sacrifices which he offered and his prayers and fastings and magic books and great diversity of rings and candles. Having succeeded in borrowing an astrolabe for a short time he made the demons explain its purpose, how to operate it, and how to make another one. Later he reformed and became bishop of Ravenna and pope.[2813] In a manuscript early in the thirteenth century is a statement that Gerbert became archbishop and pope by demon aid and had a spirit enclosed in a golden head whom he consulted as to knotty problems in composing his commentary on arithmetic. When the demon expounded a certain very difficult place badly, Gerbert skipped it, and hence that unexplained passage is called the Saltus Gilberti.[2814]
An anonymous astronomical treatise; its possible relation to Gerbert.
In a manuscript in the Bodleian library which seems to have been written early in the twelfth century[2815] is an astronomical treatise in four books which Macray suggested might be the Liber de planetis et mundi climatibus which Ethelwold, bishop of Winchester from 963 to 984, is said to have composed.[2816] The present treatise indeed embodies a Letter of Ethelwold to Pope Gerbert on squaring the circle.[2817] It seems, however, that this letter on squaring the circle was really written by Adelbold, bishop of Utrecht from 1010 to 1027.[2818] Adelbold speaks of himself in the letter as a young man[2819] and of course wrote it before Gerbert’s death in 1003, and very probably before Gerbert became Pope Silvester II in 999. But he could scarcely have written the letter early enough to have it included in a work written by Ethelwold who died in 984. Our astronomical treatise in four books is therefore not by Ethelwold, unless the letter be a later interpolation, but it is possibly by Adelbold or by Gerbert.[2820] Its opening words, “Quicumque mundane spere rationem et astrorum legem ...,” are similar to those of the treatise on the uses of the astrolabe which has often been ascribed to Gerbert, “Quicumque astronomice peritiam discipline....”[2821]
Contents of its first two books.
Our treatise then may be by Gerbert or it may be a specimen of the astronomy of the eleventh or early twelfth century. As it appears to be little known and never to have been published, it may be well to give a brief summary of its contents. An introductory paragraph outlines some of the chief points with which the treatise will be concerned, such as the twelve signs of the zodiac, their positions, “most varied qualities,” the reasons for their names, and the diverse opinions of gentile philosophers and Catholics as to their significations; the four elements; and the seven planets. In the text which follows, these topics are considered in rather the reverse order to that in which they were named in the preface. After some discussion of “the founders of astronomy and the doctors of astrology,” the first book is occupied with a description of the sphere or heavens. The second book is largely geographical, beginning with the question of the size of the earth, the zones, the ocean, and how to draw a T map. This geographical digression the author justifies in the prologue to his third book by the statement that often the position of the stars can be determined from the location of countries, and that if the habitat of peoples is known one can more easily arrive at the effect of the stars.[2822]
Attitude towards astrology.