A substantial commentary on the Kitāb al-Thamara (‘Book of the Fruit’), i.e., the Centiloquium, written by the Cairo mathematician and astronomer Abū Jaʿfar Aḥmad ibn Yūsuf ibn Ibrāhīm ibn al-Dāya sometime after 912. The commentary deals with each aphorism in turn and includes the original text put under Ptolemy’s name. According to Lemay (‘Origin and Success’), the original text was also composed by Abū Jaʿfar, who ascribed it to Ptolemy (see B.1). Abū Jaʿfar Aḥmad ibn Yūsuf ibn Ibrāhīm ibn al-Dāya is known in Latin as ‘Abuiafar Hamet filius Joseph filii Abrahe scriptor’, ‘Abugafarus’ and especially ‘Haly’ among the readers of the Centiloquium (see also C.3.1.1, Note 1) and as ‘Ametus filius Josephi’ among the readers of his mathematical works, i.e., the Liber de proportione et proportionalitate and the De arcubus similibus, both translated by Gerard of Cremona. With the sole exception of Adelard of Bath’s translation (B.1.1), it is through Abū Jaʿfar’s commentary that the Centiloquium was known in the European Middle Ages. There are five Latin translations of the text (C.3.1.1, C.3.1.2, C.3.1.3, C.3.1.4, C.3.1.5).

Bibl. M. Steinschneider, Die hebraeischen Uebersetzungen des Mittelalters und die Juden als Dolmetscher. Ein Beitrag zur Literaturgeschichte des Mittelalters, Berlin, 1893, II, 528-529; M. Ullmann, Die Natur- und Geheimwissenschaften im Islam, Leiden, 1972, 327-328; R. Lemay, ‘Origin and Success of the Kitāb Thamara of Abū Jaʿfar Aḥmad ibn Yūsuf ibn Ibrāhīm from the Tenth to the Seventeenth Century in the World of Islam and the Latin West’, in Proceedings of the First International Symposium for the History of Arabic Science (Aleppo, April 5-12, 1976), Aleppo, 1978, II, 91-107; E. R. McCarthy, ‘A Lexical Comparison of Four Twelfth Century Versions of Ptolemy’s Centiloquium from the Arabic’, in Actas del V Congreso Internacional de Filosofía Medieval, II, Madrid, 1979, 991-997: 991-992; F. Sezgin, Geschichte des arabischen Schrifttums, VII: Astrologie – Meteorologie und Verwandtes, Leiden, 1979, 157; P. Kunitzsch, review of Sezgin’s Geschichte des arabischen Schrifttums VII, Zeitschrift der Deutschen Morgenländischen Gesellschaft 132 (1982), 174-179: 175-177; R. Lemay, Abū Maʿšar al-Balḫī [Albumasar]: Liber introductorii maioris ad scientiam judiciorum astrorum, Napoli, 1995-1996, I, 115-116; IV, 16-17; VII, 58; R. Lemay, ‘Des sages antiques aux astrologues médiévaux. Falsafa et astrologie’, in La science des cieux. Sages, mages, astrologues, ed. R. Gyselen, Bures-sur-Yvette, 1999, 167-182: 172-180; R. Lemay, Le Kitāb aṯ-Ṯamara (Liber fructus, Centiloquium) d’Abū Jaʿfar Aḥmad ibn Yūsuf [Ps.-Ptolémée], 1999 [unpublished], 5 vols; M. Rinaldi, Le Commentationes in Ptolemaeum di Giovanni Giovano Pontano: fonti, tradizione e fortuna del Centiloquio pseudo-tolemaico dalla Classicità all’Umanesimo, PhD dissertation, Università degli Studi di Napoli “Federico II”, 2002, 56-60; F. Martorello, G. Bezza, Aḥmad ibn Yūsuf ibn al-Dāya: Commento al Centiloquio tolemaico, Milano-Udine, 2013; O. Pompeo Faracovi, ‘Una nuova edizione del Centiloquio’, Bruniana & Campanelliana 20 (2014), 641-644. A. Calcagno, El libro delle Cento Parole di Ptholommeo. Saggio di edizione critica del volgarizzamento fiorentino del Centiloquium pseudo-tolemaico, Milano, 2021, 7-16; M. Rinaldi, El libro delle cento parole di Ptholommeo. Volgarizzamento inedito del Centiloquium pseudo-tolemaico, Roma, 2021, xiv-xvi.

Modern ed. Critical edition, together with an Italian translation, by Martorello/Bezza. There is also an unpublished critical edition by Lemay, Le Kitāb.