HOLY TIME: Martyrologies and Calendars through the Ages

A common denominator of all history, chronology, and future planning is the need to organise time in a meaningful way – the need for a calendar (from Latin calendarium ‘account book’). How time is measured or perceived can depend on the context: time can be measured by the seasons for agricultural purposes, or by reference to important events or people, or by reference to astronomical events. In the chronicles of the Roman Empire, for instance, time was counted by the years of the emperor’s reign, and today the number of the year we live in according to the universal ‘Gregorian’ calendar is determined historically by the year of the birth of Jesus Christ. Such denominations are often culturally specific: in the Germanic tradition, the names for the days of the week refer to the Gods and the elements (Wednesday from Wodan, Friday from Frigg, etc) as opposed to the planets, like in Romance languages. Note that the modern names for Irish days of the week are mixed, having been partially supplanted by names referring to the fast: An Chédaoin ‘first fast’, An Déardaoin ‘day between the fasts’, and Dé hAoine ‘fast day’.

In the past different types of calendars have been used to ‘reckon’ time in the West. This phrase carries more meaning than you might think: before we had the atomic clock or pocket diaries, long and precise periods of time had to be calculated by reference to the cycles of the sun and moon. This became especially complex with the integration of the Christian and the Julian or ‘civil’ calendar after Christianity became the state religion of the Roman Empire. The structure of the year as we know it, and the length of the months of the year, are based on the Julian (from Julius Ceasar) calendar and determined by the length of the solar year (that is, the time it takes for the earth to revolve around the sun – roughly 365 days). The lunar year, on the other hand, which is the basis for the Christian calendar, follows the cycles of the moon (roughly 28 days).

There is a natural discrepancy of 11 days between the two, and most of the history of the Western calendar revolves around finding a way to integrate them as neatly as possible. For the Christian calendar, the calculation of Easter is essential, as it determines the date of most other feast days.  The date of Easter is officially the first Sunday after the 14th day of the Paschal full moon, provided it falls after the vernal equinox. To ascertain this date, difficult calculations are required (known as the art of computus). And when these proved incorrect – because the full moon no longer fell on the date listed in the calendar – they had to be updated, resulting in a number of heated debates as well as changes to the calendar during the medieval period.

In Late Antiquity and the early Middle Ages, calendars were primarily kept in churches, civic offices, and at court, where they became the basis for the chronicling of annual events (hence the term ‘annals’) and, in a Christian context, of the feast days and deaths of martyrs (hence ‘martyrology’) and saints. The codices selected for this exhibition contain ecclesiastical calendars and martyrologies from the medieval period, primarily from the Trinity collections and primarily focused on the Insular world (though many more could be added). The objectives of the exhibition are two-fold. It explains some of the basic features of these texts and their development from a chronological perspective, while simultanously contextualizing the differences between various texts and codices in light of the divisions in Irish society resulting from the Anglo-Norman conquest. The phrase ‘two churches’ is sometimes used to refer to the ecclesiastical sources of the later medieval period; this exhibition juxtaposes examples from each by placing them in their joint geographical and cultural framework.