Isaac ibn al-Ahdab

Itzḥak ben Shlomo ibn al-Aḥdab (or ibn al-Ḥadib) ben Tzaddiq ha-Sefardi (Hebrew: יצחק בן שלמה בן צדיק אלאחדב הספרדי, c. 1350 – c. 1426) was a Jewish mathematician, astronomer, and poet.[1]

Ibn al-Aḥdab was born in Castile to a prominent Jewish family. He was a student of Judah ben Asher II, the great-grandson of Asher ben Yeḥiel of Cologne, who was killed in the anti-Jewish massacres of 1391. By 1396 Ibn al-Aḥdab had fled Spain and was in Sicily, where he lived (in Syracuse and Palermo) until his death around 1426.[2]

Work

He studied the algebra of Maghrebi mathematician Ibn al-Bannā and published The Epistle of the Number, a translation and detailed commentary on Ibn al-Bannā's 13th century treatise Talḵīṣ ʿAmal al-Ḥisāb ("A summary of the operations of calculation").[3] The work is notable in being the first known Hebrew-language treatise to include extensive algebraic theories and operations.[4][5]

His astronomical works include Oraḥ selulah (Upraised Path), a set of tables in Hebrew for conjunctions and oppositions of the Sun and the Moon,[6] Keli Ḥemdah (Precious Instrument), which describes a unique equatorium of his own invention, functioning on the Ptolemaic theory of epicycles,[7] and Keli Memutsa (Intermediate Instrument), which describes another unique instrument of his own design, a combination astrolabe-quadrant.[7] Bernard R. Goldstein published a partial translation of Keli Ḥemdah in 1987.[7] Oraḥ selulah survives in 25 MSS, Keli Ḥemdah in 15 MSS, and Keli Memutsa in 1 MS, .[8]

He is the author of a commentary on the Passover Haggadah, titled Pesach Doros (Passover of later generations) and printed by Mekhon Bet Aharon ṿe-Yiśraʼel in 2000.[8]

Leshon ha-Zahav (Golden Language), an explication of the names for units and measurements found in the Hebrew Bible.[8]

He is probably the author of a commentary on Maimonides' Laws of the Sanctification of the Month, found in the same MS as Leshon ha-Zahav with no author given.[8]

He also wrote songs, published as Shirei Rabbeinu Itzḥak ben Shlomo ibn al-Aḥdab (1987). He is known to have composed a work called Shir ha-Shirim, but it has not survived.[8]

References
  1. Raanan, Ora, ed. (1988). The Poems of Iṣḥak ben Shlomo Al-Aḥdab (in Hebrew). Lod: Mekhon Haberman le-meḥḳere sifrut.
  2. Steinschneider, M. (1964). Mathematik bei den Juden (in German) (2 ed.). Hildensheim. p. 168.
  3. Katz, Victor (2016). "The Mathematical Cultures of Medieval Europe". History and Pedagogy of Mathematics.
  4. Wartenberg, Ilana (2015). The epistle of the number, by Ibn al-Ahdab. Perspectives on Society and Culture. Piscataway: Gorgias Press. ISBN 978-1-4632-0417-4.
  5. Reif, Stefan C. (1997). Hebrew manuscripts at Cambridge University Library: a description and introduction. Vol. 52. Cambridge University Press. ISBN 978-0521583398.
  6. Goldstein, Bernard R.; Chabás, José (2006). "Isaac ibn al-Ḥadib and Flavius Mithridates: The Diffusion of an Iberian Astronomical Tradition in the Late Middle Ages". Journal for the History of Astronomy. 37 (127): 147–172. Bibcode:2006JHA....37..147G. doi:10.1177/002182860603700202. ISSN 0021-8286. S2CID 220913612.
  7. Goldstein, Bernard R. (1987). "Descriptions of Astronomical Instruments in Hebrew". Annals of the New York Academy of Sciences. 500 (1): 105–141. doi:10.1111/j.1749-6632.1987.tb37198.x. ISSN 1749-6632. S2CID 84990297.
  8. "HebrewBooks.org Sefer Detail: הגדה של פסח - פסח דורות -- אלאחדב, יצחק בן שלמה". hebrewbooks.org. Retrieved 2021-03-19.
This article is issued from Wikipedia. The text is licensed under Creative Commons - Attribution - Sharealike. Additional terms may apply for the media files.