Abstracts of Symposium 1

Above and below the Moon: Islamicate science across the Mediterranean

Petra Schmidl
Traces of Egyptian astronomical traditions in 13th century Yemen

Since David A. King published in 1983 his “Mathematical Astronomy in Medieval Yemen”, influences of Egyptian astronomical traditions in Yemeni sources are well noted, in particular the impact of Ibn Yūnus’ astronomical-astrological handbook with tables, al-Zīj al-kabīr al-Ḥākimī, but also of al‑Marrākushī‘s instrument compendium, Jāmiʿ al-mabādiʾwa-l-ghāyāt.
After providing an overview of traces of Egyptian astronomical traditions in 13th century Yemen, this talk will focus on the oeuvre of the Rasūlid sultan al-Ashraf ʿUmar (d. 1296) and his contributions to astronomy, astrology and astronomical instruments to learn more about possible dependencies and the scholarly niveau of these works.”

Flora Vafea
The Armillary Sphere “Astrolabe” by Ptolemy according to the Description by Ḥabash al-Ḥāsib

“The armillary sphere “astrolabe” is described by Ptolemy (2nd c. AD) in chapter V.1 of his Almagest. It contains 6 rings, while the outmost ring that represents the meridian consists of two sub-rings. The instrument is used to measure the ecliptic coordinates of the sun, the moon, the planets and the fixed stars. Further descriptions of this instrument are preserved in Greek in the Commentary on the Almagest by Pappus (3rd-4th c. AD) and in the Hypotyposis astronomicarum positionum by Proclus (5th c. AD).
A description of the above instrument in Arabic is preserved in a treatise by the Persian astronomer and mathematician Ḥabash al-Ḥāsib (9th c. AD). There are at least three manuscripts containing this treatise.[1] Clear references to the “astrolabe” described by Ptolemy in the Almagest appear at the beginning and the end of the treatise. The instrument also consists of 6 rings, assembled in the same way as described by Ptolemy. However, the descriptions of the instrument construction and its use reveal further improvements from the model described in Greek sources: the positions of some fixed stars are depicted on the ring of the zodiac, the outer ring of longitude is graduated, and one more ring that represents the equator can be added to the system of rings, so that the right ascension and declination of the celestial bodies can be measured as well.
[1] Manuscripts: Messhed, Holy Shrine 5595, f. 9r-v, Topkapi, Ahmet III 3475, ff. 89r – 97v, Ayasofya 1654 ff. 105v – 109v.”

Emilio Calvo and Rosa Comes
The transmission of toponymy from Arabic astronomical treatises to Medieval Latin. The case of Plato of Tivoli’s translation of al-Battani’s zij

Most of the Medieval astronomical handbooks include geographical chapters, in which the toponyms of different places are an essential element. One of the main difficulties confronted by the Latin translators was to accurately identify those places with the real geographical ones.
The aim of our presentation is to show how this challenge is addressed by Plato of Tivoli when it comes to rendering into Latin the sixth chapter of al-Battani’s zij, which includes a number of toponyms related to the geographical ambit covered by that author, as well as the difficulties involved in the identification of these toponyms and the way they were solved.

Theo Loinaz
Medical Literature in Tenth-Century Andalus: Texts, Genres, and Sources

The apparently uncomplicated edition of Al-Ilbīrī’s Book of the Rational Conclusions (Andalus, 10th century?) has unexpectedly grown through the years into a full-fledged research on the early transmission of medical and pharmacognostical knowledge to the Islamicate west. Both manuscript witnesses appear to us as a collection of thematically related but otherwise unconnected treatises on apothecary matters, natural philosophy, medical therapy, ḫawāṣṣic lore, pharmacopoea, and dietetics. As it stands, this variegated compendium poses two main challenges: on the one hand it represents a hard-to-solve puzzle for the editor, who has to form an opinion as to whether the text as it stands, with its remarkable lacunae, is an authorial text or rather a later compilation. On the other hand the historian of science has to analyse each one of these treatises within the context of its own tradition, with due attention to the specific conventions of its genre—in order to gain some insight into the vexing matter of such qualifications as original/unoriginal, innovative/imitative which one usually feels compelled to bestow upon one’s object of study. In our contribution we would like to share with the attendants some of the problems (both philological and historiographical) that best illustrate these challenges.

Miquel Forcada
Astronomy and the sciences of the reason in 10th century al-Andalus

During the 10th century, al-Andalus (Muslim Iberian Peninsula) al-Andalus was ruled by the Umayyad caliphate. ʿAbd al-Rahmān III (r. 912-961) and al-Ḥakam II (r. 961-975) brought al-Andalus into a golden age in which culture flourished. The sciences were an important element not only in the external promotion of the dynasty but also in the cultural life of the learned elites and of the members of the dynasty. Now, whereas medicine was sponsored generously by ʿAbd al-Rahmān III, astronomy lagged behind medicine, possibly because astrology was considered as illegal by most of the religious scholars of al-Andalus. These scholars were also opposed to philosophical culture insofar as it questioned their beliefs and their sacred worldview. Astrology – therefore astronomy- and philosophy led a largely clandestine life during a part of the tenth century, yet historical evidence suggests that some scholars practised these disciplines privately and that they were tolerated to some extent. The reign of al-Ḥakam II changed the situation dramatically and astrology and astronomy flourished in a way that hat had not been seen since the previous century. They became, in much the same way as medicine, an element of the cultural life of cultivated people. The paper will explore the connections of astronomy and their practitioners to the society of Córdoba; the debates held about the legality and utility of astronomy and astrology; and the presence of astronomy in works not intended for specialists but for informed readers, like Qāsim ibn Muṭarrif’s treatise on cosmology or ʿArīb ibn Saʿīd’s calendar

Montse Diaz-Fajardo
Approximation to the alchemy of Ibn Arfa‘ Ra’s al-Andalusī (born in 1121, Jaen)

Ibn Arfa‘ Ra’s al-Andalusī was a twelfth century alchemist and author of the poem Shudhūr al-Dhahab (Pieces of Gold). He was from Jaen in southern Spain, and lived from 1121 to 1197. In this contribution, I present a chapter of his Shudhūr al-Dhahab following al-Jaldakī’s commentary, Ghāyat al-Surūr fī Sharḥ Dīwān al-Shudhūr (Extraordinary Pleasure in Commenting on the Poem Shudhūr).

Julio Samsó
Tropical versus sidereal astronomy in the Iberian Peninsula

Two astronomical schools of thought have lived together in Islamic lands. They were called since, at least, the 10th century: the Sindhind (sidereal) and the Mumtaḥan (tropical) traditions. These two schools are represented by the the two main sources which represent the Eastern Islamic input in Andalusī and Maghribī astronomy: alKhwārizmī (fl. ca. 830) and al-Battānī (d. 929).
Sidereal astronomy survived in al-Andalus and the Maghrib mainly due to astrological reasons. The Andalusī-Maghribī tradition favoured casting sidereal horoscopes. In spite of this, from the second half of the 14th century, an important change took place in Maghribī astronomy which implied the abandonment of the sidereal tradition and its replacement by the introduction of tropical Eastern zījes, like those of Muḥyī al-Dīn al-Maghribī, Ibn al-Shāṭir and, much later, Ulugh Beg. This was mainly due to the incapacity of sidereal zījes to predict planetary positions, corrected for precession, in agreement with observations.
This change took place earlier in the Christian kingdoms of the Iberian Peninsula and it seems to be due to a choice made by Jewish astronomers, beginning in the 12th century, with Abraham bar Ḥiyya and Abraham ibn ‘Ezra and culminating, in the 13th century, with the Alfonsine Tables. Several Jewish astronomers of the 14th and 15th centuries continued practising tropical astronomy, although some of them were still submitted to the influence of the Sinhind tradition, represented mainly by Ibn alKammād (first half of the 12th c.).