Our 5^th Workshop, ‘The origins of the seven-day week’, took place on the 25^th of June 2015. With it, we inaugurated a new format of very focussed workshops, which are meant to address, in turn, individual research interests of each member of our multidisciplinary team. The first workshop of this new series dealt with the theme investigated by this post’s writer. The seven-day week stems from two distinct traditions: the Biblical week of the Sabbath, and the astrological, planetary week. The main purpose of this workshop was to explore how these two traditions emerged and spread in the Roman Empire, and how they combined remarkably into a single, seven-day unit of time reckoning that was to become standard in the medieval and modern worlds.

We arranged the workshop programme into three thematic sessions: ‘The planetary week’, ‘The Jewish seven-day week’, and ‘The seven-day week in the Roman Empire’.

After a brief general introduction by Sacha Stern (UCL), Wolfgang Hübner (Münster) opened the first session with a paper entitled ‘When and where was the planetary week invented?’. An examination of the (rather scanty) relevant sources led him to confirm the general assumption that the so-called system of the chronocrators – according to which the seven ‘planets’ rule in succession the hours and days of the week – underlies the planetary week cycle. This system is based on the ‘Chaldean order’ of the planetary spheres, which would thus appear to lead back to ancient Babylonia, the birthplace of astrology; nonetheless, there are no traces of this order before the 2^nd century BCE, when astral sciences were much developed, not in Babylonia, however, but in the Hellenised Egypt of the Ptolemies. Further hints pointing to an origin of the planetary week in Hellenistic Egypt are not lacking; on these bases, Hübner proposed that this weekly system was created during the 3^rd or 2^nd century BCE in Alexandria. Béatrice Bakhouche (Montpellier) spoke about ‘Evidence of the planetary week in Rome: issues and debates’. By reconsidering part of the evidence that had already been examined in the previous talk, as well as the most significant Roman sources related to the adoption and use of the planetary week in the Roman west, she emphasised how the Romans were strongly influenced by astrological and Pythagorean ideas towards the end of the Republican period. This may have played a role in the Roman adoption of the planetary week, which, however, had initially a strictly astrological use, before evolving into a real calendrical tool. Given the limited number of sources attesting to the existence and use of this type of week in the early imperial period, she argued that the planetary week was not officially used in the Roman west earlier than the late 2^nd – early 3^rd century CE. In addition, she contributed to the question of the origins of the planetary week by stressing how a Jewish influence on the Roman calendar can hardly be assumed, considering the Romans’ general view of the Jews, which was mainly linked to an idea of marginality. Ronit Yoeli-Tlalim (Goldsmiths) offered a glimpse into a different historical and geographical context with her talk on ‘Notes on the Tibetan planetary week and its possible sources’. She pointed out that the planetary week presumably arrived to Tibet through India and, in turn, it was the Hellenic culture that transmitted this knowledge to India. Indeed, contacts and relations between Greeks and Indians go back to as early as the Hellenistic period, since the Indian campaign that Alexander the Great started a few years before his death. Unfortunately the times and modes of this transmission are not known; it is however attractive to imagine that the astrological notion of the planetary week spread towards India from Ptolemaic Egypt during the late Hellenistic period. We would thus have a further confirmation for the assumption that the planetary week originated in the Hellenised Egypt of the Ptolemies.

In the second session of our workshop, François de Blois (UCL) discussed ‘The etymology of Sabbath’. The Hebrew name for the seventh day has usually been connected with the verbal root š‑b‑t “to rest”, assuming either a denominal verb or a deverbal noun. Both of these options are, however, linguistically problematic. An alternative suggestion has been to connect it with Babylonian šapattu (or šabattu), which designates the 15^th day of the lunar month, the full moon, or a group of 15 days. This is phonologically relatively unproblematic, but it is difficult from a semantic point of view. The paper attempted to problematize this situation and offered some tentative solutions. Jonathan Ben-Dov (Haifa) enlightened us about ‘The early history of the Jewish week’. Despite the great antiquity of the Biblical seven-day week, the weekly cycle was not used as a principle for constructing the calendar in the Bible, nor is there any trace of days of the seven-day week in priestly literature. A change occurs in the Book of Jubilees, which dates to the mid-2^nd century BCE, and, slightly later, in the Qumran texts. The value of these sources as evidence that the week was used for practical purposes, however, is not certain. Days of the week are still absent from date formulae in the same period, and will make their first appearance, on ostraca, only in the 1^st century CE. Ben-Dov’s assumption is that the Jews started using days of the week for practical purposes in the 1^st century BCE; however, there are no traces of any connection of the Jewish week with the planetary week, which seemingly first appeared around the same period in the western Roman world.

My own contribution, together with that of Sacha Stern, made up the third and last session of the workshop. In my paper ‘The diversity and spread of the seven-day week in the Roman Empire’, I presented the results of the full database of literary, epigraphic, and documentary sources in Greek and Latin either including days of the week or dealing with the week, which I have been creating in approximately the last two years. I first focussed on the origins, earliest attestations, and diffusion of the planetary week in the Roman Empire, as well as on the contexts and uses of this dating system. My assumption is that although an actual calendrical use developed quite early, the planetary week first spread in the Roman west as an astrological concept, which most likely originated in Ptolemaic Egypt during the late Hellenistic period. During the imperial period the early Christians adopted the Jewish week with its six days denoted by numbers and the Sabbath as its seventh, and adapted it to their religion by dedicating the first day of the week – Sunday, the Lord’s Day – to their own God. However, the evidence shows that the Christian week did not gain much popularity, at least in the Roman west, where, despite reiterated attempts by the Church Fathers and preachers to eradicate the habit, common people, including Christians, largely continued to name the days of the week after the seven planets in late antiquity, due to the longer tradition of the planetary week in this area of the Roman Empire. Sacha Stern (UCL) discussed ‘The seven-day count in the Roman Empire: standardization and fixation.’ The main goal of this paper was to assess how standard was the reckoning of the seven-day week, i.e., to what extent, e.g., Sunday was the same day for everyone, from Ptolemaic Egypt to late Antiquity. Our database of ancient sources allowed him to carry out a statistical study, according to which in late antiquity – the period for which we have an adequate sample of certainly dated sources – the day of the week was overwhelmingly standard and in phase with ours. The study also confirmed the standard equation of planetary and Jewish/Christian days (e.g. day of Saturn = Sabbath). In the second part of his talk, he focussed on evidence covering the Ptolemaic and early Roman periods. He first showed the results of a similar, statistical study that he conducted on the material included in the Corpus Papyrorum Judaicarum, which comprises securely dated papyri, ostraca, and inscriptions from Hellenistic and Roman Egypt, written by, for, or about Jews. The working hypothesis is that Jews did not work on the Sabbath, including legal work, commerce, and financial transactions, and therefore that most documents (contracts, receipts, etc.) should not have been written on the Sabbath. On this basis, it should be possible to verify whether or not this day was in phase with the standard week. According to this study, in these early periods the week was not standard and in phase with ours. A similar result emerged from an analogous study of a dossier of receipts for the payment of the ‘Jewish Tax’ from Edfu, in Upper Egypt. This is a special tax that the Emperor Vespasian imposed on the Jews in the Roman Empire after the destruction of Jerusalem and its Temple in 70 CE. A dated graffito from Pompeii from this same period, along with the sole dated document from the Ptolemaic period included in our database, further confirmed this result, and led to the concluding conjecture that the Sabbath in Ptolemaic Egypt corresponded to what is for us Tuesday or Wednesday.

This workshop was particularly well attended, and well received by the participants. Both members of our team and external attendees generally agreed on its highly instructive value, which applied to experts on the very specific topic of the workshop and ‘neophytes’ alike.

Calendars and Religion in Antiquity and the Middle Ages, the fourth workshop of our ERC project ‘Calendars in Antiquity and the Middle Ages’, took place on 18 February 2015. With this workshop, we aimed to investigate the interaction between religion and calendars; in particular, we sought to understand whether religion has been the main factor in the formation of calendars, as may be assumed in view of the massive presence of religious content in most calendars.

In line with the multidisciplinary nature and the broad temporal scope of our project, this workshop’s programme included very varied papers, which were arranged chronologically, from Antiquity to the Middle Ages. After a brief but insightful Introduction by Sacha Stern (UCL), who emphasised how, in the time frame under consideration, the evolution of religion and calendars appears to have proceeded according to a similar pattern, from plurality to an ever increasing unity, Alasdair Livingstone (Birmingham) brought us to ancient Babylonia. His paper focussed on Babylonian Hemerologies, a large variety of texts whose common function was to determine the propitiousness or lack of it for each day of the year, often with regard to a specific activity. As one might expect, religious and cultic aspects were frequently involved in this calendrical practice. Jörg Rüpke (Erfurt) looked at the role played by religion in the Roman calendar during the Republican and early Imperial period. He argued that whilst religion was not directly related to the Republican calendar, which, in his opinion, was essentially a political-legal one, the Augustan period marked a turning point in the process of increasing inclusion of religious elements into the calendar. The ‘Feriale Duranum’, which is generally regarded as the only extant example of festival calendar used by the Roman army, was the subject of Ted Kaizer’s talk (Durham). This calendar was written on papyrus in the time of Severus Alexander (222-235 CE) and was found along with an impressive archive of documents at Dura-Europos in modern Syria. Kaizer explained how the military character of this calendar, which lists a series of festivals to be observed throughout the year, has in fact been questioned by scholars, and argued for a Palmyrene origin of some entries in the calendar.

Moving to the early Medieval period, James Palmer (St Andrews) showed that the synchronisation of the liturgical calendar, as the dispute about the date of Easter clearly exemplifies, seems to have played a key role in the Carolingian world (740-900 CE). François de Blois (UCL) spoke on ‘the ancient calendar at Mecca and the origin of the Islamic calendar’. He submitted the sources concerning the Arab calendar before Islam to a critical analysis and proposed a new hypothesis concerning the time and circumstances of the introduction of the Islamic calendar and the era of the Hijra. Nadia Vidro’s (UCL) talk explored medieval Jewish attitudes towards the unanimity of religious practice and the role of calendar in uniting the Jewish community or splitting it into factions, one desecrating the holy day of another. The diversity of these papers which, nonetheless, dealt with similar themes, along with the presence of distinguished experts in the various disciplines involved, generated several stimulating discussions and made this workshop particularly fruitful.

On 12th and 13th November 2014 the ERC Calendars project team ran our 3rd workshop ‘Images, diagrams, and tables in Antiquity and the Middle Ages’ (for our previous workshops see here).

The main idea of this workshop was to look at the use of visual devices in medieval and ancient primary sources. The programme covered a wide range of subjects, from astronomical tables in Greek papyri (Alexander Jones, New York, NYU) to the role of images as structural markers in medieval Hebrew manuscripts (Malachi Beit-Arié, Jerusalem, HUJ).

In the core area of calendars talks explored the presence, absence and layout of calendar tables in sources from different cultural areas (Sacha Stern, Nadia Vidro, UCL), the interaction between visual elements and the main prose text (Israel Sandman, Ilana Wartenberg, François de Blois, UCL), and the use of diagrams as mnemonic props for calendar reckoning (Philipp Nothaft, Warburg Institute). The programme was enhanced by presentations on diagrams in music and magic (Alexandre Cerveux, Paris-Sorbonne & EPHE and Sophie Page, UCL), on the depiction of time and space in early medieval maps (Alessandro Scafi, Warburg Institute) and on micrography (Rahel Fronda, UCL). Our discussions have greatly benefitted from illuminating comments of experts on manuscripts: Malachi Beit-Arié (Jerusalem, HUJ) and Judith Olszowy-Schlanger (Paris-Sorbonne & EPHE).

One of the themes that recurred throughout the workshop were factors behind the layout of astronomical and calendrical information. Was it determined by the purpose and the cultural context of ancient and medieval calendars? By local scribal traditions? By the material culture, such as costs and book formats? Or, perhaps, by the nature of reading, since tables are only practical for visual reading but not for reading out? Another point highlighted in many presentations was that tables and diagrams are the most vulnerable part of a text, and scribes felt free to improve, replace or leave them out completely even when copying famous established treatises. Such improvements are useful indicators of a scribe’s level of (mis-)understanding of the text that he was copying.

The flexible format of our workshops allows ample time for discussion, during sessions and over coffee and sandwiches at break times. This time as ever it was the buzz of conversations between international experts in a variety of disciplines that made the workshop particularly enriching.

Our next workshop on ‘Calendar and religion’ is planned for 18 February 2015. Details are soon to follow here.