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Geberi philosophi ac alchimistae maximi de alchimia libri tres, 1531, Chemical Heritage Foundation
Geberis philosophi perspicacissimi, summa perfectionis magisterii, 1542

Pseudo-Geber ("false Geber") is the name assigned by modern scholars to an anonymous European alchemist born in the 13th century (sometimes identified with Paul of Taranto[1]) who wrote books on alchemy and metallurgy in Latin under the pen name of "Geber".

"Geber" is the shortened and Latinised form of the name Jābir ibn Hayyān, a 9th-century Islamic alchemist. In Europe for many centuries from the 14th century onward it was assumed that "Geber" was identical with Jabir ibn Hayyan and that the books of "Geber" had been translated from Arabic. Arabic alchemy was held in high esteem by 13th century European alchemists. Pseudo-Geber adopted the name of his illustrious Arabic predecessor to attach more stature to his own work. The practice of adopting the name of an illustrious predecessor is called pseudepigraphy, and it was not uncommon in the medieval era. Similarly, a wide variety of medieval writings were distributed with the illustrious Aristotle as the stated author that were not written by the original authentic Aristotle. In the domain of alchemy and metallurgy in late medieval Europe, Pseudo-Geber's output was highly influential.

The Pseudo-Geber Corpus and the Geber Problem[edit]

The following set of books is called the "Pseudo-Geber Corpus" (or the "Latin Geber Corpus"). The books were published by printing press several times in the first half of the 16th century.[2] They were in circulation in manuscript for roughly 200 years beforehand. The stated author is "Geber" or "Geber Arabis" (Latin for "Geber the Arab"), and it is stated in some copies that the translator is "Rodogerus Hispalensis" (Latin for "Rodger of Seville").

  • Summa perfectionis magisterii ("The Height of the Perfection of Mastery").
  • Liber fornacum ("Book of Furnaces"),
  • De investigatione perfectionis ("On the Investigation of Perfection"), and
  • De inventione veritatis ("On the Discovery of Truth").


  • Testamentum Geberi
  • Alchemia Geberi

Being the clearest expression of alchemical theory and laboratory directions available until then—in a field where mysticism, secrecy, and obscurity were the usual rule—Pseudo-Geber's books were widely read and influential among European alchemists.[3] The Summa Perfectionis in particular was one of the most widely read alchemy books in western Europe in the late medieval period.[4] The next three books on the list above are shorter and are, to a substantial degree, condensations of the material in the Summa Perfectionis. The last two books listed, Testamentum Geberi and Alchemia Geberi, are "absolutely spurious, being of a later date [than the other four]", as Marcellin Berthelot put it,[5] and they are usually not included as part of the Pseudo-Geber corpus. Their author is not the same as the others, but it is not certain that the first four have the same author either.[6]

As mentioned, the Pseudo-Geber corpus was assumed to be translated from Arabic throughout the medieval and renaissance periods. This assumption was reversed in the late 19th century by the studies of Kopp, Hoefer, Berthelot, and Lippmann. The corpus is clearly influenced by medieval Arabic writers (especially by Al-Razi, and to a lesser extent, the eponymous Jabir). The estimated date for the first four books is 1310, and they could not date from much before that because no reference to the Summa Perfectionis is found anywhere in the world before or during the 13th century. For example, there is no mention in the 13th century writings of Albertus Magnus and Roger Bacon.[7] The chemistry historian J.C. Brown asserted in 1920: "An important point of evidence is the absence in the Arabic texts of the new and original facts recorded in the Latin particularly... nitric acid, aqua regia, oil of vitriol, silver nitrate...."[5] Aqua regia is a mixture of nitric acid and hydrochloric acid. Vladimir Karpenko and John A. Norris, in 2001, assert that its first documented occurrence is in Pseudo-Geber.[8] In 2005, the historian Ahmad Y. Al-Hassan pointed out that earlier Arabic texts prior to the 13th century, including the works of Jabir and Al-Razi, already contained detailed descriptions of substances such as nitric acid, aqua regia, vitriol, and various nitrates.[9]

The identity of the proposed Latin author remains a mystery. He may have lived in Italy or Spain, or both. Some books in the Geber corpus may have been written by authors that post-date the author of the Summa Perfectionis. As mentioned already, the contents of most of the other books in the corpus are mostly recapitulations of the Summa Perfectionis.[5] The one entitled De Inventione Veritatis, though mostly a recapitulation of Summa Perfectionis, has the earliest known recipe for the preparation of nitric acid."[8] The 1991 book by William R. Newman, The Summa perfectionis of Pseudo-Geber: A critical edition, translation, and study, has 250 pages of critical introduction, followed by 400 pages of footnoted Latin text and 150 pages of footnoted English translation. The critical introduction argues that the author of the Summa perfectionis was Paul of Taranto.[4]

The chemistry historian Eric John Holmyard studied the Arabic and Latin corpuses more extensively and criticized Berthelot's original hypothesis. On textual grounds, Holmyard asserted that the Latin corpus has Arabic origins. In 1924, Holmyard stated: “[Berthelot] deliberately wanted to underrate Jābir […], the choice of Jābir’s works made by Berthelot is entirely misleading.” He also stated: “It is here that Berthelot’s ignorance of Arabic led him astray. As a matter of fact, the Summa is full of Arabic phrases and turns of speech, and so are the other Latin works”.[10] In 1931, Holmyard criticized the argument that "No Arabic originals have been found", pointing to the then recent discovery of Jabir's The Book of Seventy diminishing the weight of this argument.[11] In his 1957 book Alchemy, however, Holmyard concluded that there is still considerable uncertainty regarding the origins of the Latin corpus.[12]

In 2004, the chemistry historian Maurice P. Crosland concluded that the question of Geber's identity, whether he is the original Jābir or a "pseudo-Geber" adopting his name, is "still in dispute", but nevertheless refers to Geber as "a Latin author".[13] In 2009, the chemistry historian Ahmad Y. Al-Hassan criticized Berthelot's original hypothesis and, on textual grounds, argued that the Pseudo-Geber Corpus was originally written in Arabic. Al-Hassan criticized Berthelot's lack of familiarity with the complete Arabic corpus and pointed to various Arabic Jabirian manuscripts which already contain much of the theories and practices that Berthelot previously attributed to the Latin corpus.[10]

Contents of Pseudo-Geber Corpus[edit]

Its author assumed that all metals are composed of unified sulfur and mercury corpuscles[14] and gave detailed descriptions of metallic properties in those terms. The corpus explained the use of an elixir in transmuting base metals into gold (see philosopher's stone) and defended alchemy at length against the charge that transmutation of metals was impossible. The practical directions for laboratory procedures were so clear that it is obvious the author was familiar with many chemical operations. It contains early recipes for producing mineral acids,[8] much like the earlier Arabic corpus.[10] It was not equaled in chemistry until the 16th century writings of chemist Vannoccio Biringuccio, mineralogist Georgius Agricola and alchemist Lazarus Ercker.[15]


  1. ^ William R. Newman. New Light on the Identity of Geber", Sudhoffs Archiv 69 (1985): 79-90
  2. ^ Alchemy and Early Modern Chemistry, Allen G. Debus, Jeremy Mills Publishing, 2004. ISBN 978-0-9546484-1-1.
  3. ^ Holmyard, E. J.; Jabir; Russell, Richard (September 1997). The Works of Geber. Kessinger Publishing. ISBN 978-0-7661-0015-2. Retrieved 8 June 2010. 
  4. ^ a b The Summa perfectionis of Pseudo-Geber: A critical edition, translation, and study, by William R. Newman (1991)
  5. ^ a b c Chapter VI: "The Pseudo-Geber" in A History of Chemistry from the Earliest Times (2nd ed., 1920), by J.C. Brown.
  6. ^ Long, Pamela O. (2001). Openness, secrecy, authorship: technical arts and the culture of knowledge from antiquity to the Renaissance. JHU Press. pp. 146 147. ISBN 978-0-8018-6606-7. Retrieved 14 June 2010. 
  7. ^ History of Analytical Chemistry, by Ferenc Szabadváry (1960).
  8. ^ a b c Vladimir Karpenko and John A. Norris (2001), Vitriol in the history of Chemistry.
  9. ^ Ahmad Y. Al-Hassan, Cultural contacts in building a universal civilisation: Islamic contributions, published by O.I.C. Research Centre for Islamic History, Art and Culture in 2005 and available online at History of Science and Technology in Islam
  10. ^ a b c Ahmad Y. al-Hassan, Critical-Issues Studies in al-Kimya′: Critical Issues in Latin and Arabic Alchemy and Chemistry, published as book by Olms in 2009 and as article by Centaurus journal in 2011. Online versions are available at Geber Problem @ History of Science and Technology in Islam and at Scribd.
  11. ^ Makers of Chemistry, by Eric John Holmyard (1931).
  12. ^ Eric John Holmyard, Alchemy, 1957, page 134:

    The question at once arises whether the Latin works are genuine translations from the Arabic, or written by a Latin author and, according to common practice, ascribed to Jabir in order to heighten their authority. That they are based on Muslim alchemical theory and practice is not questioned, but the same may be said of most Latin treatises on alchemy of that period; and from various turns of phrase it seems likely that their author could read Arabic. But the general style of the works is too clear and systematic to find a close parallel in any of the known writings of the Jabirian corpus, and we look in vain in them for any references to the characteristically Jabirian ideas of "balance" and the alphabetic numerology. Indeed for their age they have a remarkably matter of fact air about them, theory being stated with a minimum of prolixity and much precise practical detail being given. The general impression they convey is that they are the product of an occidental rather than an oriental mind, and a likely guess would be that they were written by a European scholar, possibly in Moorish Spain. Whatever their origin, they became the principal authorities in early Western alchemy and held that position for two or three centuries.

  13. ^ P. Crosland, Maurice, Historical Studies in the Language of Chemistry, Courier Dover Publications, 2004 1962, ISBN 0-486-43802-3, ISBN 978-0-486-43802-3, p. 15 and p. 36.
  14. ^ "The Mineral Exhalation Theory of Metallogenesis in Pre-Modern Mineral Science". John A Norris. Ambix vol. 53 no. 1, March 2006, pp. 43-56.
  15. ^ See German article de:Lazarus Ercker.