[3] A significant part of Jabir's writings deal with a philosophical theory known as "the science of the balance" (Arabic: ʿilm al-mīzān), which was aimed at reducing all phenomena (including material substances and their elements) to a system of measures and quantitative proportions.

Instead, Jabir ibn Hayyan is generally thought to have been a pseudonym used by an anonymous school of Shi'ite alchemists writing in the late 9th and early 10th centuries.

Some Arabic Jabirian works (e.g., The Great Book of Mercy, and The Book of Seventy) were translated into Latin under the Latinized name Geber, and in 13th-century Europe an anonymous writer, usually referred to as pseudo-Geber, started to produce alchemical and metallurgical writings under this name.

[5] However, he is not mentioned in any historical source before c. 900, and the first known author to write about Jabir from a biographical point of view was the Baghdadi bibliographer Ibn al-Nadīm (c.

[8] Jabir was often ignored by later medieval Islamic biographers and historians, but even early Shi'ite biographers such as Aḥmad al-Barqī (died c. 893), Abū ʿAmr al-Kashshī (first half of the 10th century), Aḥmad ibn ʿAlī al-Najāshī (983–1058), and Abū Jaʿfar al-Ṭūsī (995–1067), who wrote long volumes on the companions of the Shi'ite Imams (including the many companions of Jaʿfar al-Ṣādiq), did not mention Jabir at all.

[1] However, it has also been noted that many Jabirian treatises show clear signs of having been redacted multiple times, and the writings as we now have them may well have been based on an earlier 8th-century core.

[16] In any case, it is clear that Jabir's name was used as a pseudonym by one or more anonymous Shi'ite alchemists writing in the late 9th and early 10th centuries, who also redacted the corpus as we now know it.

[21] If he was a non-Arab Muslim client of the Azd, he is most likely to have been Persian, given his ties with eastern Iran (his nisba al-Ṭūsī also points to Tus, a city in Khurasan).

[22] According to Ibn al-Nadīm, Jabir hailed from Khurasan (eastern Iran), but spent most of his life in Kufa (Iraq),[23] both regions where the Azd tribe was well-settled.

[26] There are references throughout the Jabirian corpus to the Shi'ite Imam Jaʿfar al-Ṣādiq (died 765), whom Jabir generally calls "my master" (Arabic: sayyidī), and whom he represents as the original source of all his knowledge.

[32] However, it has recently been argued that Ḥayyān al-ʿAṭṭār probably lived at least until c. 744,[33] and that as a client (mawlā) of the Nakhaʿ tribe he is highly unlikely to have been the father of Jabir (who is supposed to have been a client/member of the Azd).

[84] However, these references may have been meant as an appeal to ancient authority rather than as an acknowledgement of any intellectual borrowing,[85] and in any case Jabirian alchemy was very different from what is found in the extant Greek alchemical treatises: it was much more systematic and coherent,[86] it made much less use of allegory and symbols,[87] and a much more important place was occupied by philosophical speculations and their application to laboratory experiments.

In the Jabirian corpus, these qualities came to be called "natures" (Arabic: ṭabāʾiʿ), and elements are said to be composed of these 'natures', plus an underlying "substance" (jawhar).

Like Zosimos, Jabir believed this would require a catalyst, an al-iksir, the elusive elixir that would make this transformation possible – which in European alchemy became known as the philosopher's stone.

[95] The sulfur-mercury theory of metals, though first attested in pseudo-Apollonius of Tyana's The Secret of Creation (Sirr al-khalīqa, late 8th or early 9th century, but largely based on older sources),[96] was also adopted by the Jabirian authors.

[98] Note that some other Latin works attributed to Jabir/Geber (Summa perfectionis, De inventione veritatis, De investigatione perfectionis, Liber fornacum, Testamentum Geberi, and Alchemia Geberi) are widely considered to be pseudepigraphs which, though largely drawing on Arabic sources, were originally written by Latin authors in the 13th–14th centuries (see pseudo-Geber); see Moureau 2020, p. 112; cf.