The calendar is an indicator for the time-consciousness of human beings and therefore related to visibility in general. The introduction of a calendar is of the utmost importance for the orientation in time, just in the same way as a map is of importance for the orientation in place. The present division of a year in twelve month, four quarters and fifty-two weeks is rather a garble of different forms of division thinking. The major two-fold division looms in the background between timekeeping based on the position of the sun or the moon.
The first signs of organized timekeeping occur in the European cultural period in the fourth century AD. The heritage of Jewish timekeeping, based on the orbit of the moon, clashed in early Christianity with the notion of time of the Romans, based on the velocity of the sun. These different approaches came, in particular, to a head in the elaborated way to calculate the day of Eastern. ‘The Christian era, with its years AD arose from attempts to calculate the festival of Easter by a luni-solar calendar’ (HARRISON, 1976).
The eastern, lunar calculation placed the Resurrection of Christ on the first full moon after the spring-equinox. This is not necessarily a Sunday. In the western idea Easter should be on a Sunday, so there was the problem. On the Counsel of Nicea in 325 AD – where the Holy Trinity was established – the two points of view stood opposite to each other.
Eventually, the Western way prevailed. Easter is now on the Sunday closest to the first full moon on the day of or after the spring-equinox. This period can vary from one to thirty-five days in the period between the 21st of March and the 25th of April (COWIE & GUMMER, 1974; STRUBBE & VOET, 1960/1991). Tables of the day of Easter were created to indicate the day long in advance (fig. 60).
Fig. 60 – Calendar with the days of Easter on the church wall of the Eglise Saint-Etienne de la Cite (Old Cathedral) in Perigueux (Dordogne, France). In: CORDOLIANI (1964). The inscription was not found when I visited the place in 2007, but then a restoration had sealed off the greater part of the terrain.
Fig. 61 – Eglise Saint-Etienne de la Cite (Old cathedral) in Perigueux (Dordogne, France). ‘Nicknamed “the big mosque” by Victor Hugo, the Saint-Front Cathedral stands out with its Byzantine style and 5 cupolas. The name Périgueux comes from Petrocorii, a Latinization of Celtic words meaning “the four tribes” – the Gallic people that held the area before the Roman conquest. Périgueux was their capital city. In 200 BC, the Petricorii came from the North and settled at Perigueux and established an encampment at La Boissière. After the Roman invasion, they left this post and established themselves on the plaine of L’Isle, and the town of Vesunna was created. This Roman city was eventually embellished with amenities such as temples, baths, amphitheatres, and a forum. At the end of the third century AD, the Roman city was surrounded by ramparts, and the town took the name of Civitas Petrocoriorum. In the 10th century, Le Puy-Saint-Front was constructed around an abbey next to the old Gallo-Roman city. It was organised into a municipality around 1182′ (Wikipedia). Photo: Marten Kuilman (2007).
The ‘Chronica’ of Hiëronymus contained the first design of a time-table. The translation in 380 AD. of Eusebius of Caesarea provided the structural setting of Augustinus’ ‘De Civitate Dei‘. The system became more precise as Dionysius Exiguus applied the year-tables of St. Cyril of Alexandria in 525 AD. The latter wrote – in the early fifth century – a history started with Diocletian (240 AD). Dionysius Exiguus extended the period to the birth of Christ by introducing the ‘anno ab incarnationes domini nostri Jesu Christi‘ (BORST, 1990; DECLERCQ, 2002) (fig. 62). This approach was gradually – in a process spanning several centuries – accepted as the actual ‘beginning’ of Western time-calculation.
Fig. 62 – Easter cycle of Dionysius Exiguus. Marble. Ravenna, 6th cent. Museum Ravenna.
In: BORST, 1990.
Victoris Tonnennensis (c. 567) was the first on record to use the Christian calendar (NEWTON, 1972). The calendar of Dionysius was officially proclaimed as standard on the Council of Whitby (England) in 664 AD. From this time onwards the study and registration of chronology became a major occupation. Bede’s ‘De Temporum Ratione’, dated in 725 AD, was the most notable and influential product of these efforts (fig. 63).
Fig. 63 – Calendar of Bede. Irish manuscript, Laon of Soissons, c. 850. Landesbibliothek Karlsruhe. In: BORST (1990).
The ‘Frankish Annals’ (741 – 788; the ‘Annales Laurissenses’), the ‘Annales Einhardi’ (788 – 829) and the ‘Liber Pontificalis‘ (over the life of the popes between the sixth century and 887) indicated a further general time-consciousness.
The ‘Annals of Donegal’ are of importance in Ireland. These stories were collected between 1632 and 1636 by Michel O’Clery and three assistants. They became later known as the ‘Annals of the Kingdom of Ireland by the Four Masters’ (O’DONOVAN, 1851; GOUGAUD, 1911). The most complete version of Irish historical writings was formed by the ‘Annals of Ulster‘ (HUGHES, 1972).
Einhardt (775 – 840), scholar and courtier
The period around 900 AD was ‘a low-water mark of historical writing in France and Germany’ (POOLE, 1926). A sharp increase in the number of chronicles, with history-writers like Herman the Cripple of Reichenau, Bernold of Constance and Sigebert of Gembloux, took place after 1050. This pattern fitted into the overall trend to reach for an ‘empirical’ visibility towards the twelfth century.
The library of St John’s College in Oxford is in the possession of a compilation manuscript (MS 17), dated from the late eleventh and early twelfth century. It contains copied work of Bede, Heinric of Auxerre, Byrhtferth (of Ramsay), astronomical tables, part of the ‘Arithmetica’ of Boëthius and a discussion over the abacus. Folio 3v contained the date 1110. The moon tables (on f. 29) started in 1083 (HASKINS, 1924/1960).
Further critical remarks on the calendar are made in this same period. The calculations of Dionysius were studied, for instance, by Gerland in his ‘Computus’ (1081, MS lat. 11260, f7v.), Marianus Scottus (1028 – 1082) and in the anonymous ‘Liber decennalis in modum dialogi compositus’ (Bibl. Angelica, Rome. MS 1413, ff. 1 – 24).
Bacon suggested to pope Clement IV – in his ‘Opus Majus’ (Paris, 1267) – to change the calender (DUHEM, 1958; III, p. 412). Action was only taken some three hundred years later in 1582 as an advisory-commission for pope Gregory X proposed to lapse ten days (from 5 to 15 Oct.) to correct the Julian calendar (based on 365,25 days in a year) (COYNE et al., 1983; GIMPEL, 1988). The leap year (bissextile), once every four years, makes up the difference. An extra correction takes place on the turn of the century, when only years, which could be divided by four, get an extra day (on the 29th of February).
From this short survey emerges a confusing pattern. All types of division seem to mix in pluriformity: three hundred and sixty four (or five) days in a year, hundred (century), sixty (minutes in an hour), fifty-two weeks, thirty days (in a month), twelve month (in a year), seven days (in a week), four quarters (in an hour), three quarters (in a year), two (day and night) are all figures with a different division-background and do not indicate any specific prominence in time. However, they all point to the importance of ‘division’ as a guiding entity to tackle the realm of the infinity (of time).
Making a calender (as an event) is a decision on division. It marks a distinct moment of historic consciousness, which is closely related to the (quadralectic) understanding of visibility.
BORST, Arno (1990). Computus. Zeit und Zahl in der Geschichte Europas. Bnd. 28 in: Kleine Kulturwissenschaftliche Bibliothek. Verlag Klaus Wagenbach, Berlin. ISBN 3 8031 51287
DECLERCQ, G. (2002). Dionysius Exiguus and the Introduction of the Christian Era. Pp. 165 – 246 in: Sacris Erudiri. Vol. 41. Brepols Publishers. ISSN 0771-7776
CORDOLIANI, A. (1964). La table pascale de Perigieux. pp. 57 – 60 in: Cahiers des Civilisation Medievale X – XII Siecles. Centre d’etudes superieures de civilisation medievale. Tome IV. Universite de Poitiers.
COWIE, Leonard W. & GUMMER, John S. (1974). The Christian Calender. A complete guide to the seasons of the Christian year, telling the story of Christ and the Saints from Advent to Pentecoast. Weidenfeld and Nicolson, London. ISBN 0 297 76804 2
COYNE, G.; HOSKIN, M. & PEDERSON, O. (Ed.) (1983). Gregorian Reform of the Calender. Proc.of the Vatican Conference to Commemorate Its 400th Anniversary. 1582 – 1982. Specola Vat., Vatican City.
DONOVAN, O’, John (Ed.) (1851). Annals of the Kingdom of Ireland by the Four Masters. 6 Vol., Dublin.
DUHEM, Pierre (1958). Le Système du Monde. Histoire des doctrines cosmologiques de Platon a Copernic. Tome I – IV. Hermann, Paris.
GIMPEL, Jean (1979/1988). The Medieval Machine. The Industrial Revolution of the Middle Ages. Futura, London/Scolar Press, Aldershot, England.
GOUGAUD, Louis (1911). Les chrétientés celtiques. J. Gabalda, Paris.
HARRISON, Kenneth (1976). The Framework of Anglo-Saxon History to AD 900. Cambridge University Press, Cambridge.ISBN 0 521 20935 8
HASKINS, Charles H. (1924/1960). Studies in the History of Mediaeval Science. Frederick Ungar Publishing Co., New York.
HUGHES, Kathleen (1972). Early Christian Ireland. Introduction to the Sources. The Camelot Press Ltd./The Sources of History Limited, London. ISBN 0 340 16145 0
NEWTON, Robert R. (1972). Medieval Chronicles and the Rotation of the Earth. The John Hopkins University Press, Baltimore/London. ISBN 0-8018-1402-2
POOLE, Reginald L. (1926). Chronicles and annals. A brief outline of their origin and growth. Clarendon Press.
STRUBBE, E.I. & VOET, L. (1960/1991). De chronologie van de Middeleeuwen en de moderne tijden in de Nederlanden. Standaard Boekhandel, Antwerpen/Amsterdam; Palais des Academies/Paleis der Academiën, Bruxelles/Brussel.