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CALENDAR

CALENDAR. It was widely recognized in the early sixteenth century that the calendar was inaccurate, but the question of how it should be reformed and who had the authority to do so raised fundamental issues. It was some two hundred and fifty years before all of Europe had changed.

The Christian Church had adopted the Julian calendar from the Roman Empire at the Council of Nicaea in 325 C.E.: the first general council of the church, its authority acknowledged thereafter by East and West, Protestants and Catholics. A slight error in the original Roman calculations had by 1500 accumulated to ten days, leaving the real spring equinox on 11 March instead of 21 March. What really bothered the Roman Catholic Church (though not, apparently, the Orthodox Church) was the error this produced in the date of Easter. This was supposed to fall on the Sunday on or after the full moon after 21 March, but it now often fell a month late relative to the real equinox. Nicolaus Copernicus's De Revolutionibus Orbium Caelestium (1543; On the revolutions of the celestial orbs) had originally been commissioned as a basis upon which to reform the calendar, but the intervening Reformation and Copernicus's heretical views about the solar system overlaid the issue.

One of the last acts of the Counter-Reformation Council of Trent was to order a reform of the calendar, which it was hoped would provide a basic measure of agreement between Protestants and Catholics on at least one fundamental issue. The observations and calculations were undertaken by the Jesuit astronomer Christoph Clavius (1537–1612), and the results embodied in Pope Gregory XIII's bull of 1582. Ten days were to be removed from October 1582 to bring the calendar back in line with the seasons, and the system of leap years was modified to keep it on track; from then on there was to be a leap year only at the end of every fourth century, and not of every century as before. The old formula for calculating the date of Easter was modified but retained. The Gregorian reform was fundamentally religious rather than astronomical, and the Roman Catholic Church continued to reject Copernicus.

Only a handful of countries (Spain, Portugal, Poland, and parts of Italy) adopted the new Gregorian calendar on time, not least because the bull was promulgated so late. By 1585 most Roman Catholic countries had followed. Most Protestant states—including large parts of Switzerland, Germany, the Protestant Low Countries, Great Britain, and Scandinavia—retained the Julian calendar for another century or more, creating a patchwork of calendrical practice throughout Europe, particularly complex in the Holy Roman Empire. The key issue was not astronomical accuracy but papal authority. By accepting a papal bull, states would appear to be recognizing the authority of the pope not only to interfere in civil affairs but also to alter decisions of the early church; indeed, most Roman Catholic countries took care to adopt the new calendar by their own civil acts. In England, the mathematician and astrologer John Dee (1527–1608) argued that the time of Christ, rather than that of the early church, was the appropriate "radix of time" for Protestants, and proposed his own Elizabethan imperial calendar one day ahead of Rome, but his views were unwelcome to the authorities and in the end England did nothing.

In 1700, with the gap between the two calendars set to widen to eleven days, most Protestant states followed a resolution of the imperial Diet of Regensburg and adopted a modified version of the Gregorian calendar. They did so using their own calculations, following the German astronomer Johannes Kepler (1571–1630), and substituting an astronomical Easter for the traditional version, to the same practical effect. In Britain, where antipopery remained strong, the new calendar was not adopted until September 1752, when eleven days were omitted and a third Easter calculation adopted, also to identical effect. Sweden pursued its own course, coming fully into line in 1753. The churches of the East remained unmoved, standing fast by the decisions of early Christendom; the fast-secularizing states of eastern Europe generally went Gregorian for civil purposes around the time of World War I.

PRACTICAL PROBLEMS

Did the calendar change create practical, as opposed to political, problems? Undoubtedly it did, especially in international communications and where Protestant and Catholic jurisdictions were interspersed, as in much of central Europe and the Low Countries. The modest disruption of the familiar relationship between the feasts of the church and the seasons was quite quickly overcome, but the actual details varied according to how the reform was implemented. In Britain in 1752, for example, the eleven days September 3–13 inclusive were omitted from the calendar, bringing human events eleven days forward in the natural year. Fairs however were left at the same place in the natural year, putting their calendar dates back by eleven days (although many fairs in practice moved forward). Financial payments too kept their full natural term, leaving the financial year ending on 5 April rather than the traditional 25 March. At the same time, the start of the legal year was altered from 25 March to 1 January. The arrival of the new Christmas Day eleven days early took many by surprise in a society that still reckoned by feasts and fairs as much as by dates and diaries. There was widespread resistance and resentment, although the tale that people rioted for their eleven lost days is a myth. In Bohemia and in Augsburg, though, there were several years of strife between Catholics and Protestants over the issue in the 1580s, known as the "Kalenderstreit."

In navigating between old-style and new-style calendars, it is necessary to remember that in general Roman Catholic states were ten days ahead of Protestant and Orthodox states from 1583 until 1700. Care must be taken in the 1580s, and with Britain, Sweden, the Netherlands, and Switzerland. Catholic minorities in Protestant states may have adopted either calendar for religious purposes. For clarity, historians often note "O.S." or "N.S." after Julian and Gregorian dates respectively.

The issue of the calendar is a reminder that the reference points for the calculation of time express the most basic assumptions of society. The disputes it engendered were symptomatic of religious and political divisions in a world where nothing could be taken for granted.

See also Copernicus, Nicolaus; Dee, John; Kepler, Johannes; Time, Measurement of; Trent, Council of.

BIBLIOGRAPHY

Cheney, C. R. A Handbook of Dates for Students of British History. Rev. ed. London, 2000.

Coyne, G. V., M. A. Hoskin, and O. Pedersen, eds. Gregorian Reform of the Calendar: Proceedings of the Vatican Conference to Commemorate its Four Hundredth Anniversary, 1582–1982. Vatican City, 1983.

Poole, Robert. Time's Alteration: Calendar Reform in Early Modern England. London, 1998.

Richards, E. G. Mapping Time: The Calendar and Its History. Oxford and New York, 1998.

Whitrow, G. J. Time in History: The Evolution of Our General Awareness of Time and Temporal Perspective. Oxford, 1988.

ROBERT POOLE