Origins and Transmission of Liber Abraham Iudei de Nativitatibus
The Liber Abraham Iudei de Nativitatibus is a Latin astrological treatise that has no surviving Hebrew counterpart, and whose affiliation with Abraham Ibn Ezra (ca. 1189-ca. 1160) is unclear. Till now De nativitatibus has been known to modern scholarship almost exclusively through the first print edition, produced in Venice in 1485. Building on the mention in the print edition of 1154 as the date of composi- tion, it has been argued that De nativitatibus was written in Latin by Ibn Ezra or with his active participation for a Latin readership. The present paper presents a totally new picture by taking into account the evidence provided by virtually all the available manuscript witnesses of this text and other unknown sources. It will be shown that the archetype of De nativitatibus was written in Hebrew by Ibn Ezra, that De nativitatibus was composed in Latin in 1166 or slightly later, when Ibn Ezra was no longer alive, that De nativitatibus was transmitted in four very different versions, and that one of these versions was written by Henry Bate, who first translated into Latin a collection of Ibn Ezra’s astrological writings.
Revue des études juives, 177 (3-4), 2018, pp. 317-352.
Calculating Birth: Abraham Ibn Ezra’s Role in the Creation and Diffusion of the Trutina Hermetis
"For the doctrine of nativities, concerned with making predictions about the fate of individuals and regarded since Antiquity as the core of the art, the time for which the horoscope should be cast is the precise instant of birth.
But this was the Achilles’ heel of the doctrine of nativities, because people do not generally know or remember the precise moment of their birth. Consequently, an essential component of virtually every treatise on the doc- trine of nativities, whether in Greek, Arabic, Hebrew, Latin, or the European vernaculars, is the ‘rectification of the nativity’, a term that designates a variety of procedures to determine the ascendant of the natal horoscope when the time of birth is not known (the usual situation). One approach, perhaps the most famous of all and that with which we are concerned here, had long gone by the curious name trutina Hermetis, that is, the ‘balance of Hermes’. The main char- acteristic of this method, as we shall see, is that it takes account of the duration of pregnancy in order to ‘rectify’ the nativity. With the trutina Hermetis, the time of conception and the instant of birth become an astrological instrument of calculation, denying or correcting a piece of information that had always been under female control.
This paper scrutinizes the role that the trutina Hermetis played in the work of Abraham Ibn Ezra (1089–1167), both his astrological treatises and his biblical commentaries."
In: Pregnancy and Childbirth in the Premodern World: European and Middle Eastern Cul- tures, from Late Antiquity to the Renaissance, ed. by Costanza Gislon Dopfel, Alessandra Foscati, and Charles Burnett, (Turnhout: Brepols, 2019) pp. 79–106
The medieval Moon in a matrix: double argument tables for lunar motion
Astronomers have always considered the motion of the Moon as highly complicated, and this motion is decisive in determining the circumstances of such critical celestial phenomena as eclipses. Table-makers devoted much ingenuity in trying to find ways to present it in tabular form. In the late Middle Ages, double argument tables provided a smart and compact solution to address this problem satisfactorily, and many tables of this kind were compiled by both Christian and Jewish astronomers. This paper presents multiple examples of the diversity of approaches adopted by compilers of tables who used this powerful tool, and brings to light intellectual interactions among them that are otherwise hidden from view.
Archive for History of Exact Sciences · March 2019