The Jewish Calendar in Early Islamic Sources

A Leverhulme-Funded Research Project

This research project started in May 2010 is in run in conjunction with the AHRC-funded major research project on ‘Medieval Monographs on the Jewish Calendar’, which deals with Hebrew monographs on the Jewish calendar from early 12th-century Spain and in France .

The social and cultural importance of calendars was recognized by all faiths in the Middle Ages, and this explains why medieval scholars became interested in the calendars of faiths other than their own. Islamic scientists and chronographers from the 9th-11th centuries wrote extensively about the Jewish calendar, and their works are an invaluable source of evidence on the rabbinic calendar in this early period. Just as the 12th-century Jewish authors on the same subject, their expositions of the Jewish calendar constitute a rich blend of astronomy and mathematics with the study of chronology, social practices, and religious traditions. They also reflect early Islamic attitudes to Judaism.

This project is focused on the colossal monograph of Abu Rayhan al-Biruni, known in English as Chronology of the Ancient Nations, written in Arabic c.1000 CE, which contains substantial sections on the Jewish calendar and its historical origins. A new edition and translation of the relevant sections of this work will be prepared on the basis of the best manuscripts, which hitherto have been unpublished. Other relevant works of al-Biruni will also be surveyed, as well as a number of tracts on the Jewish calendar that were written in these centuries by several Islamic authors including the eminent mathematician al-Khwarezmi, al-Qaini, and other anonymous authors, which will be similarly edited, elucidated, and published. Questions will be raised about the sources and accuracy of these Islamic writers, why they took the trouble to describe the Jewish calendar, and what these works reveal about the culture and society in which they were produced.

The project is funded by the Leverhulme Trust with an award of £104,790, running from May 2010 to April 2012. It is led by Professor Sacha Stern (as Principal Investigator), an expert on ancient and medieval Jewish calendars and Principal Investigator of the AHRC-funded project (see above), and Professor Francois de Blois (as Project Researcher), a distinguished scholar who has already made a substantial contribution to the study of al-Biruni and of Islamic and Iranian calendars.