Medieval Christian and Jewish Calendar Texts

A Leverhulme-Funded Research Project

The social and cultural importance of calendars was recognized by all faiths in the Middle Ages, which explains why medieval scholars became interested in the calendars of faiths other than their own. Jewish and Christian scholars in the English Midlands, northern France, and western Germany of the 12th - 15th centuries produced a substantial literature on calendars. Although they each focussed on their own tradition, they also took a great interest in each other's calendars: Christians wrote extensively about the Jewish lunar calendar, and Jews about the Julian calendar and the computation of the date of Easter. These writings combined, in rich and variegated forms, the subjects of calendars, chronology, astronomy, and liturgy.

This Leverhulme-funded research project will survey a large number of Hebrew and Latin calendar manuscripts that have been largely neglected until now in modern scholarship, prepare critical editions and translations of the texts, and investigate their broader historical and cultural implications. It will explore how information about calendars was exchanged between Christian and Jewish medieval scholars, and what motivated this unique manifestation of scholarly Christian-Jewish relations. It will also investigate how the study of calendars by Christians and Jews contributed to scientific developments in the field of astronomy and mathematics, as well as being grounded in the religious, liturgical practices of their respective religious traditions.

The project is funded by the Leverhulme Trust with an award of £134,338, running from October 2011 to September 2013. It is led by Professor Sacha Stern (as Principal Investigator), an expert on ancient and medieval Jewish calendars and currently Principal Investigator of other research projects within the Department on the theme of medieval calendars: 'Medieval monographs on the Jewish calendar' (funded by the AHRC) and 'The Jewish calendar in early Islamic sources' (funded by the Leverhulme Trust). Most of the research for this project is carried out by Justine Isserles and Philipp Nothaft as Postdoctoral Research Associates. Justine Isserles is an expert in Jewish medieval liturgical-legal compendia from Franco-Germany in the tradition of the Mahzor Vitry, which contain substantial sections on Jewish and Christian calendars; Philipp Nothaft is an expert in Christian, Latin medieval texts on the computation of the date of Easter and the development of scientific chronology.