Claudius Ptolemaus. Der Sternkatalog des Almagest: Die arabisch-mittelalterliche Tradition, Teil II: Die lateinische Ubersetzung Gerhards von Cremona; Teil III: Gesamt-konkordanz der Sternkoordinaten.

• Author: Saliba, George

These two handsome volumes are the second and third in a series of three volumes devoted to the project of the Ptolemaic star catalogue in medieval times; the first, devoted to the Arabic translations from Greek was discussed by the present reviewer in JAOS 109 (1989): 694-96.

In comparison with the Arabic tradition treated in the first volume, the Latin tradition taken up in the second is much more difficult to deal with. The difficulty of editing two separate Arabic translations of the Almagest in volume one, that of al-Hajjaj b. Matar (completed around A.D. 830) and of Ishaq-Thabit (completed toward the end of the same century), based on some eight extant manuscripts in total, fades by comparison with the more daunting task of editing the Latin translation, based on some 43 to 50 manuscripts, if we count the manuscripts of the complete text, the fragments, and the related texts. To add to the difficulty, Gerhard of Cremona, the translator of the Latin version, seems to have worked from both Arabic versions, instead of limiting himself to one. But in all instances he also followed very closely whichever Arabic text he was using, almost word for word. In a way, this slavish rendering of the Arabic turned out to be a mixed blessing, for on the one hand it allowed Kunitzsch to determine which of the two Arabic versions was being used at every instance, but it also doubled his labors by forcing him to check the Latin translation against two Arabic versions instead of one. He has brilliantly accomplished this task, and in addition allowed the modern reader to tell at a glance which sections, or portions thereof, derived from the Hajjaj translation by marking them in italics, while he has left the sections deriving from the Ishaq-Thabit translation in roman type.

Moreover, since the Almagest star catalogue deals essentially with descriptions of stars, i.e., describing their position on specific constellations, and with their longitude, latitude and magnitude, it thus contains a large list of numbers that can be read correctly only if the numeral system is easy to follow. In the case of the Arabic alphabetic numeral system, commonly used in such high-ranking astronomical texts as the Almagest translations, the difficulty was encountered when numbers such as 15, 35, 55, or 6, 7, or 17, 47, are easily confused when rendered poorly in Arabic script. One would think that this difficulty would be alleviated in the Latin tradition, but then one notes...