This is the Arabic version of Ptolemy’s most important cosmological work, known as Planetary Hypotheses, in which he provides a physical interpretation of his astronomy in two books. Although not as famous as the Almagest, the Planetary Hypotheses triggered a lifely discussion in the medieval Islamic world about the relationship between (Aristotelian) natural philosophy and (Ptolemaic) astronomy, as evident for example from Ibn al-Haytham’s al-Shukūk ʿalā Baṭlamyūs (C.1.11). Alternative titles: Kitāb Iqtiṣāṣ aḥwāl al-kawākib; Fī Iqtiṣāṣ jumal aḥwāl al-kawākib al-mutaḥayyira (manuscripts); Fī Uṣūl ḥarakāt al-kawākib al-mutaḥayyira (Thābit ibn Qurra); Kitāb al-Manshūrāt (al-Bīrūnī).

Origin: The extant Greek version of the Planetary Hypotheses only contains the first part of Book I (up to Chapter I.14). As the three medieval Latin translations all depend on this truncated version (see Latin A.3.1, A.3.2, and A.3.3), the Arabic version is – aside from the Hebrew translation made from the Arabic (Steinschneider) – the only complete witness of the entire text. The authenticity of the Arabic version is confirmed by its agreement with Greek fragments from Chapters I.17 and II.12 in Proclus and Simplicius (Jones).

The Arabic translator is not known for certain, although there are two slight indications speaking for al-Ḥajjāj, the famous translator of the Almagest (A.1.1) and of Euclid’s Elements (see Hullmeine, ‘Ptolemaic Astronomy’, p. 15). According to MS Leiden, UB, Or. 180 (f. 2r), Thābit b. Qurra was responsible for the revision (iṣlāḥ) of the Arabic translation. This has been doubted by modern scholarship due to the allegedly poor quality of the translation (Murschel, p. 34). However, a close comparison between the extant parts of the Greek and the corresponding Arabic did not confirm this poor quality (Hullmeine, ‘Ptolemaic Astronomy’, pp. 9–16). The first Arabic reference to the Planetary Hypotheses can be found in a treatise by Thābit ibn Qurra (Morelon, ‘Thābit ibn Qurra’), which suggests that it was translated in the 9^th century ce.

Content: In Book I, Ptolemy provides an update and summary of the planetary models (Chapters 1–14), the most important feature of which is the new latitude theory (Nikfahm-Khubravan, pp. 99–114). This is followed by a discussion of planetary distances and sizes as well as anomalies and optical problems (Chapters 15–21, discussed in detail by Goldstein). Book II deals with the question of how the circles in the planetary models from the Almagest and Book I of the Planetary Hypotheses can be translated into a coherent physical system. It starts with a philosophical discussion on the origin and transmission of celestial motions (Chapters II.1–9) and proceeds with a description of the physical planetary models. Of particular importance for the Arabic reception are Ptolemy’s theory of planetary distances and his replacement of some of the celestial spheres with ring-shaped segments, so-called ‘sawn-off pieces’ (manshūrāt), hence the alternative title Kitāb al-Manshūrāt that was used by al-Bīrūnī (Hartner).

Text: [ed. Hullmeine]

[Book I, Part 1] (pp. 27–61) كتاب بطلميوس القلودي في اقتصاص جمل أحوال الكواكب المتحيّرة. المقالة الأولى. إنّا قد وصفنا الأصول التي عليها مبنى الحركات السماوية يا سوري في الأقاويل التي وضعناها في الأمور التعليمية. — وكان بعد الكوكب من منتهى الشمال من الفك المائل الصغير على ما يتلو من فلك البروج مائتي جزء وتسعة عشر جزءًا وستّ عشرة دقيقة.

[Book I, Part 2] (pp. 61–83) هذه هيئة الكواكب المتحيّرة في أفلاكها. وعلى حسب ما قلنا يشبه أن يكون السبب الذي من أجله يظهر للحركات السماوية اختلاف غير عارض في كرة الكواكب الثابتة بوجه من الوجوه. — فإنّها تكون أنقص من النسبة التي هي لها كالحال في الأبعاد لعجز البصر كما قلنا عن تمييز وإدراك أقدار كمّية تفاضل كلّ نوع ممّا ذكرنا. تمّت المقالة من كتاب بطلميوس القلودي في اقتصاص جمل أحوال الكواكب المتحيّرة.

[Book II] (pp. 85–137) المقالة الثانية من هذا الكتاب. أمّا ما يدرك من نسب الحركات الفلكية بالأرصاد التي كانت إلى وقتنا هذا فقد وصفنا أكثره. —والذي يجتمع من الجداول الرابعة هو بعد مركز الكوكب من منتهى شمال الفلك المائل عن فلك التدوير إلى ما يتلو من القوس العليا. تمّت المقالة الثانية من كتاب بطلميوس القلودي في اقتصاص جمل أحوال الكواكب المتحيّرة. وهي تمام الكتاب.

Bibl.: Ibn al-Nadīm, Fihrist (ed. FlügelGustav Flügel, Kitâb al-Fihrist, 2 vols, Leipzig: Vogel, 1871–1872, vol. I, p. 268; English tr. DodgeBayard Dodge, The Fihrist of al-Nadīm. A Tenth-Century Survey of Muslim Culture, 2 vols, New York / London: Columbia University Press, 1970, vol. II, p. 640); Ibn al-Qifṭī, Taʾrīkh al-ḥukamā (ed. LippertJulius Lippert, Ibn al-Qifṭī’s Taʾrīḫ al-ḥukamā, Leipzig: Dieterich, 1903, p. 98). — Moritz Steinschneider, Die hebraeischen Uebersetzungen des Mittelalters und die Juden als Dolmetscher, Berlin: Kommisionsverlag des Bibliographischen Bureaus, 1893, pp. 538–539; GAS VIFuat Sezgin, Geschichte des arabischen Schrifttums. Vol. VI: Astronomie bis ca. 430 H., Leiden: Brill, 1978, pp. 94–95. — Johan Ludvig Heiberg, Opera astronomica minora, Leipzig: Teubner, 1907, pp. vi–x, clxvi–clxxiv, and 69–145; Willy Hartner, ‘Mediaeval Views on Cosmic Dimensions and Ptolemy’s Kitāb al-Manshūrāt’, in I. Bernard Cohen and René Taton (eds), Mélanges Alexandre Koyré, vol. I: L’aventure de la science, Paris: Hermann, 1964, pp. 254–282; Bernard R. Goldstein, The Arabic Version of Ptolemy’s Planetary Hypotheses, Philadelphia: American Philosophical Society, 1967; Noel M. Swerdlow, Ptolemy’s Theory of the Distances and Sizes of the Planets: A Study of the Scientific Foundations of Medieval Cosmology, PhD dissertation, Yale University, 1968; Abdelhamid I. Sabra, ‘The Andalusian Revolt against Ptolemaic Astronomy. Averroes and al-Biṭrūjī’, in Everett Mendelsohn (ed.), Transformation and Tradition in the Sciences. Essays in Honor of I. Bernard Cohen, Cambridge: Cambridge University Press, 1984, pp. 133–153, here pp. 150–151; Régis Morelon, Thābit ibn Qurra. Œuvres d’astronomie, Paris: Les Belles Lettres, 1987, p. 104; Eulalia Pérez Sedeño, Las hipótesis de los planetas, Madrid: Alianza, 1987; Roshdi Rashed, ‘Fūthīṭos (?) et al-Kindī sur “l’illusion lunaire”’, in Marie-Odile Goulet-Cazé, Goulven Madec and Denis O’Brien (eds), ΣΟΦΙΗΣ ΜΑΙΗΤΟΡΕΣ. « Chercheurs de sagesse ». Hommage à Jean Pépin, Paris: Institut d’Études Augustiniennes, 1992, pp. 533–559, here pp. 558–559; Aurora Cano Ledesma and Eulalia Pérez Sedeño, ‘«Las hipotesis de los planetas» de Claudio Ptolomeo y su recepcion entre los astronomas arabes’, Revista Brasileira de História da Ciência 10 (1993), pp. 21–28; Régis Morelon, ‘La version arabe du Livre des hypothèses de Ptolémée’, Mélanges de l’Institut Dominicain d’Etudes Orientales 21 (1993), pp. 7–85; Liba Taub, Ptolemy’s Universe: The Natural Philosophical and Ethical Foundations of Ptolemy’s Astronomy, Chicago: Open Court / La Salle, 1993, pp. 105–134; Andrea Murschel, ‘The Structure and Function of Ptolemy’s Physical Hypotheses of Planetary Motion’, Journal for the History of Astronomy 26 (1995), pp. 33–61; Régis Morelon, ‘Le Livre des hypothèses de Claude Ptolémée et la lecture de cet auteur en langue arabe’, in Ahmad Hasnawi, Abdelali Elamrani-Jamal and Maroun Aouad (eds), Perspectives arabes et médiévales sur la tradition scientifique et philosophique grecque. Actes du Colloque de la SIHSPAI (Societé Internationale d’Histoire des Sciences et de la Philosophie Arabes et Islamiques), Paris, 31 mars - 3 avril 1993, Leuven / Paris: Peeters / Institut du Monde Arabe, 1997, pp. 95–104; Elizabeth Anne Hamm, Ptolemy’s Planetary Theory: An English Translation of Book One, Part A of the Planetary Hypotheses with Introduction and Commentary, PhD dissertation, University of Toronto, 2011; Sébastien Moureau, ‘Note on a Passage of the Arabic Translation of Ptolemy's Planetary Hypotheses’, in Luis Arturo Guichard, Juan Luis García Alonso and María Paz de Hoz (eds), The Alexandrian Tradition. Interactions between Science, Religion, and Literature, Bern etc.: Peter Lang, 2014, pp. 93–95; Paul Hullmeine, ‘Was there a Ninth Sphere in Ptolemy?’, in David Juste, Benno van Dalen, Dag Nikolaus Hasse and Charles Burnett (eds), Ptolemy’s Science of the Stars in the Middle Ages, Turnhout: Brepols, 2020, pp. 79–96; Alexander Jones, ‘The Ancient Ptolemy’, in David Juste, Benno van Dalen, Dag Nikolaus Hasse and Charles Burnett (eds), Ptolemy’s Science of the Stars in the Middle Ages, Turnhout: Brepols, 2020, pp. 13–34, here pp. 20–22; Roshdi Rashed and Erwan Penchèvre, ‘Ibn al-Haytham et le mouvement d’enroulement’, Arabic Sciences and Philosophy 30 (2020), pp. 27–137; Paul Hullmeine, Ptolemaic Astronomy in the Cosmological Debates in Classical Arabic Thought. With an Edition of the Arabic Text of Ptolemy’s Planetary Hypotheses, PhD dissertation, LMU Munich, 2021; Guillaume Loizelet, Mesurer et ordonner les astres d’al-Farghānī à al-Bīrūnī : la tradition arabe du Livre des Hypothèses de Ptolémée (IXe-XIe s.). Avec une édition et une traduction française du chapitre X.6 d’al-Qānūn al-Masʿūdī d’al-Bīrūnī, PhD dissertation, Université de Paris, 2021; Sajjad Nikfahm-Khubravan, The Reception of Ptolemy’s Latitude Theories in Islamic Astronomy, PhD dissertation, McGill University, 2022.

Ed.: The complete Arabic text was edited and translated into English by Hullmeine (‘Ptolemaic Astronomy’, pp. 25–138). The partial Greek edition by Heiberg faces a complete German translation made on the basis of the Arabic manuscripts by Ludwig Nix, Frants Buhl, and Boul Heegaard. Based on the Greek edition, the first half of Book I was translated into English by Hamm. Goldstein was the first to note that the second part of Book I, which was omitted in Heiberg, is extant in Arabic and published an English translation and facsimile edition of the London manuscript. Morelon (‘La version arabe’) edited the entire Book I and translated it into French. The following chapters were edited separately: Chapter I.21 (Rashed), a part of Chapter II.12 (Rashed & Penchèvre, pp. 120–126), and Chapters I.10-15 (Nikfahm-Khubravan, pp. 569–581).