ISAAC IBN AL-HADIB AND FLAVIUS MITHRIDATES: THE DIFFUSION OF AN IBERIAN ASTRONOMICAL TRADITION IN THE LATE MIDDLE AGES

摘要

Isaac Ibn al-Hadib (or al-Ahdab) first appears in the literature, when he was in Castile in the 1370s, as a student of Judah ben Asher Ⅱ (then resident in Burgos), the great-grandson of Asher ben Yehiel of Cologne (d. c. 1328) who became chief rabbi of Toledo in 1305. Judah ben Asher Ⅱ (d. 1391) composed a set of astronomical tables that are poorly preserved in a unique copy; he was killed during the anti-Jewish riots that took place all over Spain beginning in 1391 and, as a result of these riots, many Jews left Spain around that time. Ibn al-Hadib was a member of a prominent Jewish family in Castile and arrived in Sicily no later than 1396 when the island was ruled by Joan Ⅰ (d. 1396), King of Aragon and eldest son of Pere Ⅲ of the house of Barcelona. Both Pere and Joan were keen on astronomy and had Jewish scholars at the royal court. Ibn al-Hadib's main astronomical work was a set of tables in Hebrew for conjunctions and oppositions of the Sun and the Moon, called Orah selulah ["the paved way": cf. Prov. 15:19]. This text is mentioned by several later astronomers, notably by Abraham Zacut in chapter 5 of his Great composition (ha-Hibbur ha-gadol), composed in 1478. Ibn al-Hadib died in Sicily around 1426.