The Arabic version of the Planetary Hypotheses, which, unlike the Greek and the three Latin translations made from the Greek, survives in full. The authenticity of the part of the Arabic version not surviving in Greek is confirmed by its agreement with Greek fragments from chapters I.17 and II.12 in Proclus and Simplicius (Jones). Although not as widely known as the Almagest, the Planetary Hypotheses triggered a lively 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). 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).

Origin: The Arabic translator is not known with certainty, but the exact agreement of the translation of certain technical terms with the Almagest translation by al-Ḥajjāj make him a serious candidate (see Hullmeine, Ptolemy’s Cosmology, pp. 20–21). According to the title page of MS Leiden, UB, Or. 180, f. 2r, the manuscript contains a revision (iṣlāḥ) of the Arabic translation by Thābit b. Qurra. 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 has not confirmed this poor quality (Hullmeine, Ptolemy’s Cosmology, pp. 15–22). The earliest Arabic reference to the Planetary Hypotheses can be found in Thābit b. Qurra’s treatise on lunar crescent visibility (Morelon, Thābit ibn Qurra), which suggests that the Planetary Hypotheses was translated in the third/ninth century.

Content: In Book I, Ptolemy provides a summary of the planetary models (chapters 1–14), which partially updates those from the Almagest, most importantly with a new latitude theory (Nikfahm-Khubravan, pp. 99–114). This is followed by a discussion of planetary distances and sizes as well as the anomalies of the planetary motions and optical problems (chapters 15–21, discussed in detail by Goldstein). Book II deals with the question of how the purely geometrical planetary models from the Almagest and Book I of the Planetary Hypotheses can be explained by a physical theory. 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 (chapters II.10–18).

Text: [ed. Hullmeine, Ptolemy’s Cosmology]

[Book I, Part 1] (pp. 222–260) 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. 262–286) 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. 288–350) 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, al-Fihrist (ed. FlügelGustav Flügel, Kitâb al-Fihrist, 2 vols, Leipzig: Vogel, 1871–1872, vol. I, p. 268:11; ed. SayyidAyman Fu’ād Sayyid, Kitāb al-Fihrist li-Abī l-Faraj Muḥammad bin Isḥāq al-Nadīm (allafa-hu sana 377 H), 4 vols, London: Al Furqan Islamic Heritage Foundation, 2009{vol. III, p. 216:1–2}; 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). — J. L. 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; GAS VIFuat Sezgin, Geschichte des arabischen Schrifttums, Vol. VI: Astronomie bis ca. 430 H., Leiden: Brill, 1978, pp. 94–95 (no. ii); 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, Claudio Ptolomeo. 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 astronomos arabes’, Revista Brasileira de História da Ciência 10 (1993), pp. 21–27; Régis Morelon, ‘La version arabe du Livre des hypothèses de Ptolémée’, Mélanges de l’Institut Dominicain d’Etudes Orientales 21 (1993), pp. 7–85; 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: Peeters / Paris: Institut du Monde Arabe, 1997, pp. 95–104; 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: 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; 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; Paul Hullmeine, Ptolemy’s Cosmology in Greek and Arabic. The Background and Legacy of the Planetary Hypotheses, Turnhout: Brepols, 2024.

Ed.: German translation of the first part of Book I (facing the Greek edition) and the entire Book II from two Arabic manuscripts (Leiden and London) by Ludwig Nix, Frants Buhl, and Poul Heegaard in Heiberg, pp. 69–145. Facsimile of the full Arabic text from the London manuscript, including the second part of Book I and Book II, together with an English translation of the second part of Book I, in Goldstein. Critical edition of the Arabic text of Book I with a French translation in Morelon, ‘La version arabe’. Separate editions of: Chapter I.21 (Rashed), a part of Chapter II.12 (Rashed & Penchèvre), and Chapters I.10-15 (Nikfahm-Khubravan, pp. 569–581). Critical edition of the complete Arabic text, together with an English translation, in Hullmeine, Ptolemy’s Cosmology, pp. 222–351.