Calendar and science by Nadia Vidro
Zutot: Perspectives on Jewish Culture 20, 87–97, 2023
The Book of Commandments of the influential Qaraite scholar Levi b. Yefet is traditionally dated ... more The Book of Commandments of the influential Qaraite scholar Levi b. Yefet is traditionally dated 1006/7 CE. This date is based on the Hebrew translation of the Book of Commandments and is irreconcilable with a calendrical characteristic of this year provided by Levi b. Yefet. In this article I propose to revise the date of composition of the Book of Commandments to 1009 CE. This date is given in a copy of the Arabic original of the code and is calendrically consistent. I also discuss events in the calendar of Palestinian Qaraites that prompted Levi b. Yefet to mention the year in which he was writing and that took place due to irregular weather patterns.
Jewish Studies Quarterly 30/3, 259–280, 2023
Throughout the ages setting the calendar by lunar observation has been one of the most salient Qa... more Throughout the ages setting the calendar by lunar observation has been one of the most salient Qaraite practices and a key component of the Qaraite religious identity. It is asserted in a variety of sources belonging to many different genres and can sometimes stand as a synecdoche for the entirety of Qaraite customs. The present article analyses the method of setting months by sighting the crescent as it is described in Qaraite legal and exegetical works from the 10th-11th centuries and compares it with the Jewish observational calendar and the Muslim calendar. The article also looks at the implications for the religious observance of a calendar in which beginnings of months could not be known in advance, and discusses attitudes to and the lived experience of calendar diversity that existed within the Qaraite movement and between Qaraites and Rabbanites.
Aleph: Historical Studies in Science and Judaism 22/1–2, pp. pp. 125-156, 2022
One of the most salient divisions between medieval Rabbanites and Qaraites was in the field of ca... more One of the most salient divisions between medieval Rabbanites and Qaraites was in the field of calendar. Qaraites and Rabbanites disagreed on how to determine which years to intercalate (i.e., to extend with the insertion of a thirteenth month) in order to keep up with the seasons. While the Rabbanites used a fixed nineteen-year cycle of intercalation, the Qaraites maintained that intercalation must be based on the state of ripeness of barley crops in Palestine. This created problems for Qaraite communities outside of the Land of Israel, many of whom found it impossible to receive information about the state of crops in Palestine in time to celebrate Passover. This article investigates how medieval Qaraite Diaspora communities made a decision to intercalate. Based on a wide range of sources many of which were not previously discussed, it studies the Diaspora communities' approaches to empirical intercalation and provides an in-depth analysis of the Qaraites' attitude toward and use of mathematical methods, such as the method of the vernal equinox and the Rabbanite nineteen-year cycle of intercalations. The article also reflects on the attitude of Palestinian Qaraite ideologists toward the calendar situation in the Diaspora and argues that the division between Qaraites as adherents of an empirical intercalation vs. Rabbanites as followers of a fixed calculated scheme was never clear-cut when considered in the context of the entire Qaraite Jewish community, and of lived practice rather than ideology.
Le Muséon, 2021
A Jewish text from the Cairo Genizah (T-S Ar.29.56), written in Judeo-Arabic, provides a list of ... more A Jewish text from the Cairo Genizah (T-S Ar.29.56), written in Judeo-Arabic, provides a list of the dates of Lent and Easter in the Coptic calendar starting from 930 CE; four years of the roster are preserved. In this article, the text of T-S Ar.29.56 is edited and translated, followed by commentary and discussion. This is one of the very few medieval Jewish texts from Islamic lands that engages with the Christian Easter calendar, and it evidences a sound understanding of its computation. Remarkably, it proposes to correct the epact and hence the dates of Lent and Easter, apparently to bring them more in line with the actual phases of the moon – more than two centuries before Christian scholars in the West began to call for correction of the Easter computation. The author of our text may have corrected the dates of Easter on the basis of the molad, the time of the new moon as calculated in the Jewish calendar.
Aleph: Historical Studies in Science and Judaism 21.1, 149–87 , 2021
The correct way of setting the calendar was a matter of much debate among medieval Jews. While it... more The correct way of setting the calendar was a matter of much debate among medieval Jews. While it is well-known that medieval Rabbanite and Qaraite communities practiced different calendars, the Jewish calendar landscape of the ninth– tenth centuries appears to have been much more diverse. Medieval sources suggest that Jewish groups in that period used calendars based on a variety of principles including observation, different calculations, and a combination of observation and calculation. No in-depth examination exists of medieval alternatives to the Rabbanite calendar. This article is a study of non-Rabbanite medieval Jewish calendars described in tenth-century Babylonian works the Kitāb al-Tamyīz and the Commentary on Genesis
by Saadia Gaon, and Kitāb al-Anwār wal-Marāqib by Jacob al-Qirqisānī. In addition to analysing the calendation methods described in the sources, I assess the trustworthiness of Saadia and al-Qirqisānī’s reports and suggest that they reflect real calendars of the period with some degree of accuracy.
Ginzei Qedem 17, 11*–49*, 2021
In this article I reconstructed from unpublished and partly unidentified manuscripts the beginnin... more In this article I reconstructed from unpublished and partly unidentified manuscripts the beginning of discourse VII of al-Qirqisānī’s legal code Kitāb al-Anwār, missing in Leon Nemoy’s standard edition of the code. I presented an annotated edition and translation of Kitāb al-Anwār, discourse VII, chapter 1. This chapter is important for the study of historical Jewish calendars because it contains a listing of various schemes for setting months and identifies Jewish groups who supported these schemes. A comparison of Kitāb al-Anwār, discourse VII, chapter 1 with Saʿadya’s commentary on Genesis 1:14 demonstrates significant verbatim overlap between the two texts and suggests that al-Qirqisānī embedded in Kitāb al-Anwār passages from Saʿadya’s commentary on Genesis without identifying them as quotations. That al-Qirqisānī borrowed passages from Saʿadya’s commentary, possibly written in the same year, highlights how quickly books in 10th-century Babylonia were read and integrated into the scholarly discourse. Importantly, these borrowings transcended Qaraite and Rabbanite divisions.
Journal of Jewish Studies 72/2, 283–312 , 2021
One of the most salient medieval Qaraite practices was setting the calendar by observation of nat... more One of the most salient medieval Qaraite practices was setting the calendar by observation of natural phenomena. While the Rabbanites followed arithmetical schemes, Qaraites set months by sighting the new moon and intercalated years on the basis of the state of ripeness of barley crops (aviv). Multiple Qaraite treatises on the aviv are preserved, but documentary evidence of empirical intercalation is scarce, making it difficult to learn how it was performed in practice. This article examines two Qaraite calendar chronicles that document barley observations and decisions regarding intercalation in a range of years in the eleventh century. They shed important light on how the Qaraite calendar operated over periods of time and attest to frequent calendar difference within the Qaraite movement and between Qaraites and Rabbanites. The chronicles make it clear that the Qaraite calendar of the period was not a monolithic system counterposed to that of the Rabbanites.
S. Stern (ed.), Calendars in the Making: The Origins of Calendars from the Roman Empire to the Later Middle Ages, 2021
This paper traces the history of the Jewish 247-year calendar cycle based on evidence provided by... more This paper traces the history of the Jewish 247-year calendar cycle based on evidence provided by a comprehensive corpus of medieval and early modern manuscripts from different geo-cultural areas. It gauges popular and scientific attitudes towards the reiterative calendar asking why, although this cycle was known to be “faulty” already in the 12th century, reiterative calendars continued to be copied and discussed until the 19th century.
Abstract
Many medieval and early modern Jewish calendars were based on the assumption that the c... more Abstract
Many medieval and early modern Jewish calendars were based on the assumption that the calendar repeats itself exactly after 247 years. Although this cycle – famously referred to as the ʿIggul of R. Naḥshon Gaon – is discussed in many sources from medieval to modern, its origins are still a mystery. The present article attempts to shed light on the early history of reiterative Jewish calendar by looking at the oldest 247-year cycles identified to date. The sources, discovered in the Cairo Genizah, demonstrate that the 247-year cycle originated in Babylonia in the middle of the 10th century and was put together by Josiah b. Mevorakh (ibn) al-ʿĀqūlī, previously known from Judaeo-Persian calendar treatises. In contrast, a large body of manuscript evidence shows that the attribution of the cycle to R. Naḥshon Gaon (874–882 CE) is not attested before the 12th century and may be unhistorical. The 247-year cycle may have been proposed as an alternative Jewish calendar that would eliminate the need for calculation and prevent calendar divergence. But at least from the early 12th century the cycle was seen as a means of setting the standard calendar, even though it is not fully compatible with the latter.
The published version is available on Jstor http://www.jstor.org/stable/10.2979 and on Project Muse https://muse.jhu.edu/article/652312
Journal of Jewish Studies, 2018
This article is a case study in the creation, transmission and evolution of calendar tables in me... more This article is a case study in the creation, transmission and evolution of calendar tables in medieval and early modern Jewish sources. It looks at calendar tables in Arba̔ah Ṭurim by Jacob ben Asher (early fourteenth century), one of the most influential rabbinic codes of law. Calendar tables in printed editions of Arba̔ah Ṭurim (Ṭur Oraḥ Ḥayyim, chapter 428) deviate from the normative rabbinic calendar and can lead to celebrating religious holidays at the wrong times. The inclusion of non-standard tables in an authoritative code of law has long raised questions about their authenticity. This article examines the history of calendar tables in Ṭur Oraḥ Ḥayyim by investigating all extant manuscripts and fifteenth- to sixteenth-century printed editions of the code. The article highlights the unstable connection of calendar tables with authorial compositions and the lack of calendar expertise among copyists and users of calendar tables.
Jewish Studies Quarterly, 2019
This article studies Nahshon Gaon’s association with the Jewish calendar. Nahshon ben Zadok Gaon,... more This article studies Nahshon Gaon’s association with the Jewish calendar. Nahshon ben Zadok Gaon, a ninth-century head of the academy of Sura, is credited with developing a system of calendation known as the Iggul of R. Nahshon, which is considered the Gaon’s most reliably attributable work. Based on a corpus of more than 200 medieval and early-modern sources, this article questions the historicity of this attribution. It identifies six different calendar schemes ascribed in the sources to Nahshon Gaon under the title Iggul and demonstrates that such attributions are pseudoepigraphic and predominantly Ashkenazi. Nahshon Gaon’s name first appears in late 12th-century Ashkenazi calendar sources, linked to a reiterative cal- endar for 247 years. Other schemes copied under the title Iggul are later, and their attribution to Nahshon Gaon reflects the fact that the Gaon came to be perceived as a calendar authority.
The contrast between scientific, scholarly knowledge and popular lore and culture affected all ar... more The contrast between scientific, scholarly knowledge and popular lore and culture affected all areas of Jewish medieval society, including the ways time and calendars were reckoned. The sixth workshop of the ERC project, Calendars in Antiquity and the Middle Ages, explored the conflict, tension, and complementarity between science and popular culture in a variety of fields and disciplines ranging from law and custom to mathematics, medicine, alchemy and magic.
This is a blog on the workshop, with links to full-length audio-recordings of all talks
(originally posted here: http://blogs.ucl.ac.uk/calendars-ancient-medieval-project/2016/01/11/science-versus-popular-culture-in-medieval-jewish-society/).
This is a blog about a conference “Calendars in Antiquity and the Middle Ages” that took place at... more This is a blog about a conference “Calendars in Antiquity and the Middle Ages” that took place at UCL on 3–5 July 2017. This conference presented the outcomes of the ERC-funded project “Calendars in Antiquity and the Middle Ages: Standardization and Fixation”, on the history and evolution of calendars in late antique and medieval societies, together with contributions from international collaborators in the field.
The blog includes references to full-length audio-recordings of most talks.
Originally posted at http://blogs.ucl.ac.uk/calendars-ancient-medieval-project/2017/09/11/conference/
Hebrew and grammar by Nadia Vidro
Leiden: Brill, 2014
A Universal Art. Hebrew Grammar Across Disciplines and Faiths reflects on medieval and early mode... more A Universal Art. Hebrew Grammar Across Disciplines and Faiths reflects on medieval and early modern Hebrew linguistics as a discipline that crossed geographic and religious borders and linked up with a plethora of scholarly activities, from Judaeo-Arabic Bible translations to the Renaissance search for the holiest alphabet. This collection of articles presents a cross-section of new research avenues on Hebraism, Karaite, Rabbanite and Christian, with an emphasis on the transmission of linguistic ideas through time and space among different communities, cultures and religious currents. The resulting picture is one of intrinsic variation and dynamic growth as opposed to the linear paradigm of development, culmination and stagnation current in the historiography of Hebrew linguistics.
Readership: All interested in the history of Hebrew linguistics and the transmission of Hebrew grammatical knowledge between the Jewish and the Christian intellectual traditions, those concerned with Bible translations, Hebrew scientific terminology, and Christian Hebraism.
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Calendar and science by Nadia Vidro
by Saadia Gaon, and Kitāb al-Anwār wal-Marāqib by Jacob al-Qirqisānī. In addition to analysing the calendation methods described in the sources, I assess the trustworthiness of Saadia and al-Qirqisānī’s reports and suggest that they reflect real calendars of the period with some degree of accuracy.
Many medieval and early modern Jewish calendars were based on the assumption that the calendar repeats itself exactly after 247 years. Although this cycle – famously referred to as the ʿIggul of R. Naḥshon Gaon – is discussed in many sources from medieval to modern, its origins are still a mystery. The present article attempts to shed light on the early history of reiterative Jewish calendar by looking at the oldest 247-year cycles identified to date. The sources, discovered in the Cairo Genizah, demonstrate that the 247-year cycle originated in Babylonia in the middle of the 10th century and was put together by Josiah b. Mevorakh (ibn) al-ʿĀqūlī, previously known from Judaeo-Persian calendar treatises. In contrast, a large body of manuscript evidence shows that the attribution of the cycle to R. Naḥshon Gaon (874–882 CE) is not attested before the 12th century and may be unhistorical. The 247-year cycle may have been proposed as an alternative Jewish calendar that would eliminate the need for calculation and prevent calendar divergence. But at least from the early 12th century the cycle was seen as a means of setting the standard calendar, even though it is not fully compatible with the latter.
The published version is available on Jstor http://www.jstor.org/stable/10.2979 and on Project Muse https://muse.jhu.edu/article/652312
This is a blog on the workshop, with links to full-length audio-recordings of all talks
(originally posted here: http://blogs.ucl.ac.uk/calendars-ancient-medieval-project/2016/01/11/science-versus-popular-culture-in-medieval-jewish-society/).
The blog includes references to full-length audio-recordings of most talks.
Originally posted at http://blogs.ucl.ac.uk/calendars-ancient-medieval-project/2017/09/11/conference/
Hebrew and grammar by Nadia Vidro
Readership: All interested in the history of Hebrew linguistics and the transmission of Hebrew grammatical knowledge between the Jewish and the Christian intellectual traditions, those concerned with Bible translations, Hebrew scientific terminology, and Christian Hebraism.
by Saadia Gaon, and Kitāb al-Anwār wal-Marāqib by Jacob al-Qirqisānī. In addition to analysing the calendation methods described in the sources, I assess the trustworthiness of Saadia and al-Qirqisānī’s reports and suggest that they reflect real calendars of the period with some degree of accuracy.
Many medieval and early modern Jewish calendars were based on the assumption that the calendar repeats itself exactly after 247 years. Although this cycle – famously referred to as the ʿIggul of R. Naḥshon Gaon – is discussed in many sources from medieval to modern, its origins are still a mystery. The present article attempts to shed light on the early history of reiterative Jewish calendar by looking at the oldest 247-year cycles identified to date. The sources, discovered in the Cairo Genizah, demonstrate that the 247-year cycle originated in Babylonia in the middle of the 10th century and was put together by Josiah b. Mevorakh (ibn) al-ʿĀqūlī, previously known from Judaeo-Persian calendar treatises. In contrast, a large body of manuscript evidence shows that the attribution of the cycle to R. Naḥshon Gaon (874–882 CE) is not attested before the 12th century and may be unhistorical. The 247-year cycle may have been proposed as an alternative Jewish calendar that would eliminate the need for calculation and prevent calendar divergence. But at least from the early 12th century the cycle was seen as a means of setting the standard calendar, even though it is not fully compatible with the latter.
The published version is available on Jstor http://www.jstor.org/stable/10.2979 and on Project Muse https://muse.jhu.edu/article/652312
This is a blog on the workshop, with links to full-length audio-recordings of all talks
(originally posted here: http://blogs.ucl.ac.uk/calendars-ancient-medieval-project/2016/01/11/science-versus-popular-culture-in-medieval-jewish-society/).
The blog includes references to full-length audio-recordings of most talks.
Originally posted at http://blogs.ucl.ac.uk/calendars-ancient-medieval-project/2017/09/11/conference/
Readership: All interested in the history of Hebrew linguistics and the transmission of Hebrew grammatical knowledge between the Jewish and the Christian intellectual traditions, those concerned with Bible translations, Hebrew scientific terminology, and Christian Hebraism.
Publication year: 2018
Publisher: Acta Universitatis Upsaliensis
Editors: Nadia Vidro, Ronny Vollandt, Esther-Miriam Wagner, Judith Olszowy-Schlanger
Available to download (open access): www.diva-portal.org/smash/get/diva2:1192909/FULLTEXT01.pdf
A paperback version will also be available soon for purchase:
http://acta.mamutweb.com/Shop/List/-Studia-Semitica-Upsaliensia-ISSN-0585-5535/74/1