. “Calendar” has three distinct meanings. In the broadest sense, it refers to the astronomical calendar that provides the context for the other meanings; it is also applied to the annual cycle of ecclesiastical festivals; and it refers to the document that appears at the beginning of a liturgical book.
The astronomical calendar in use throughout western Europe in the Middle Ages is the Julian calendar, so-called for its establishment under Julius Caesar in 46 B. C. It defines a year as consisting of 365 and a quarter days, requiring an additional day every fourth, or leap, year. (This is some eleven minutes longer than the true astronomical year, creating the need for the corrections of the Gregorian calendar worked out under Pope Gregory XIII in 1582: the omission of ten days in October 1582 and the subsequent omission of the leap year in years divisible by 100 but not 400.) The Julian calendar utilized the twelve months of modern usage but had no weeks. The seven days of the week, named after the seven planets as then understood, were added in the 2nd century. The seven-day week, long maintained in the Jewish calendar, greatly influenced the Christian calendar, which replaced the Sabbath by Sunday as the principal day.
The annual round of liturgical dates is divided into a temporal and a sanctoral cycle. The temporal cycle, or temporale, consists of Sundays and the feast days commemorating the events of the life of Jesus Christ. There is a lesser sequence of fixed dates associated with Christmas and the Epiphany, December 25 and January 6; and a major sequence associated with Easter, which is celebrated on the Sunday after the first full moon of spring. The precise calculation of Easter’s date, involving differences over the astronomical calendar and other issues, was the subject of intense controversy in the early Middle Ages. The sanctoral cycle, or sanctorale, includes the feast days of saints; these are celebrated on the date of their death, a practice stemming from the fact that the early sanctorale is derived from the Martyrology, itself originating as a calendar commemorating the date and place of a martyr’s passion. The temporal and sanctoral festivals were interspersed in the early-medieval liturgical books but eventually separated.
The calendars that preceded liturgical books generally devoted one page to each month beginning with January. One line, in turn, was devoted to each day of the month, giving the name and type of its feast, or left blank if none occurred. In the left-hand margin were three columns of numbers and letters. The inner one gave the date of the month, usually according to the Roman system of nones, ides, and kalends. A second gave the so-called dominical letters, a series of the first seven letters of the alphabet, repeated continuously over the twelve months of the year; thus, whatever letter stood next to the first Sunday of a given year would point to the remainder of its Sundays. Finally, the outer column of numbers called the “golden numbers,” encoded the annual lunar tables in such a way so that if they were used in conjunction with the dominical letters a knowledgeable person could calculate the date of Easter for any year.
In the later Middle Ages, calendars were often the subject of special artistic attention, displaying two twelve-fold series of illustrations: the signs of the zodiac and the labors of the month. The latter in particular were sometimes splendidly executed, as in the celebrated full-page miniatures of the Tres Riches Heures of John of Berry. These book paintings, in turn, influenced some of the earliest easel paintings, like Breugel’s great series on the months of the year.
James McKinnon
[See also: BOOK OF HOURS; CANONICAL HOURS; DIVINE OFFICE; MASS, CHANTS AND TEXTS]
Frere, Walter. Studies in Early Roman Liturgy. London: Oxford University Press, 1930, Vol. 1: The Kalendar.
MacArthur, A. Allan. The Evolution of the Christian Year. London: SCM, 1953.
Thurston, Herbert. “Calendar.” In The Catholic Encyclopedia. New York: Appleton, 1908, Vol. 3, pp. 158-66.
World History
