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Calendars in Late Antiquity and the Middle Ages: Standardization and Fixation


A major research project funded by an Advanced Grant of the European Research Council (ERC)

This research project studies the evolution of calendars in late antique and medieval societies, with a special focus on Roman, Christian, Jewish, and Islamic calendars. The complex evolution of these calendars was closely related to politics, science, and religion, and contributed more widely to the standardization of culture in the ancient and medieval worlds.

The project is based in the Department of Hebrew and Jewish Studies, with Professor Sacha Stern as Principal Investigator and five Research Associates working in several areas including the seven-day week, late antique hemerologia, medieval Jewish calendar disputes, and medieval Arabic and Hebrew monographs on astronomy and calendars. It is funded by an ERC Advanced Grant to the value of €2,499,000, the largest ever achieved in the Faculty of Arts and Humanities.

Tel Fara Plaque
Tel Fara Plaque, Courtesy of UCL Institute of Archaeology
From Sacha Stern, 'Counting time with peg holes', in M. Carnall (Ed.), 'Conversation Pieces: Inspirational objects in UCL's historic collections' (pp. 68-69). Oxford, UK: Shire Publications Ltd, 2013.

The study of calendars has been neglected by historians as a merely technical curiosity; but in fact, the calendar was at the heart of ancient and medieval culture, as a structured perception of time, and as an organizing principle of social life. Our study of calendars covers a wide range of historical periods and cultural traditions, and employs a wide range of disciplines: social history, ancient and medieval astronomy and mathematics, the study of religions, literature, epigraphy, and codicology. We are interested to discover how Roman, Christian, Jewish, and Islamic calendars evolved, in late Antiquity and the Middle Ages, towards ever increasing standardization and fixation.

To this end, we are focusing on five specific manifestations of this process:

  1. the diffusion and standardization of the seven-day week in the Roman Empire;
  2. 'hemerologia' (comparative calendar tables) and their production in late Antiquity;
  3. the Jewish calendar dispute, between Palestinians and Babylonians, of 921-2 CE;
  4. Jewish calendar fixed cycles in medieval manuscripts;
  5. monographs on the calendar by medieval Muslim, Christian, and Jewish scholars, especially al-Biruni’s 'Chronology of the Ancient Nations' and Isaac Israeli’s 'Yesod Olam'

Study of these five research areas will enable us to formulate a general interpretation and explanation of how and why calendars became increasingly standardized and fixed. Our Research Associates and their main research areas are:

Workshops on project-related themes are organized on a regular basis, with the participation of international experts and open access to the public.