Cécile Treffort, Université de Poitiers (CESCM), Institut universitaire de France
In the old Romanesque cathedral of Périgueux (Saint-Étienne-de-la-Cité), a “Paschal table” can be seen on the south wall of the choir, a list of 91 consecutive dates of Easter preceded by a short heading: “This is the date of Easter without term or number. When you have finished it, start at the beginning“. The starting year of this sort of perpetual calendar is not mentioned in the inscription, but for various reasons it can be attributed to the middle of the 12th century.
The date of Easter, a major Christian festival, was fixed at the Council of Nicaea in 325 as the first Sunday after the full moon of the spring equinox. Its date, calculated according to the course of the moon, was therefore mobile within a solar calendar. The art of ecclesiastical computation (from computus, calculation) aimed, among other things, to determine the date of Easter each year and thus to align the Easter cycle (from the beginning of Lent 40 days before Easter to Pentecost 50 days afterwards) with the whole of the liturgical year.
Although there are many computational tables in medieval manuscripts, few of them are displayed, painted or engraved, on the walls of churches: the one in Périgueux is an exception, and one can legitimately wonder about the reasons and the stakes of such an inscription. The conference will begin with a “technical” presentation of the table, from a material and archaeological point of view. In a comparative perspective, it will then compare it with the different monumental calendars known for the Middle Ages, and the main principles of the comput. The last part will be devoted to a more historical study, in order to determine the local conditions that led the bishop to have such a table engraved in the wall of his cathedral, a kind of staging of liturgical time to be put in relation with the episcopal policy of the time.