Opinion | Why Is The Gregorian Calendar Still Counting Converts?
The love for tradition kept the Eastern Orthodox Church from adopting the Gregorian calendar though it was based on reason and mathematics
On July 28, 2023, amidst the war in Ukraine, President Volodymyr Zelenskyy approved a law advancing the date of Christmas in Ukraine from January 7 to December 25. An average person would be bemused to know that Christmas was previously celebrated anywhere in the world on a date different from the universally known December 25.
While for Zelenskyy, it was a political move to distance Ukraine’s Orthodox Church from its Russian heritage, it reveals how sections of the Eastern Orthodox Church still followed the Julian calendar for liturgical use, though the nations they inhabit have long shifted to the Gregorian calendar for all other purposes. Therein hangs a tale about calendar reforms.
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The astronomical basis of the Gregorian calendar was too sound to be scientifically rejected. It restored the equinoxes and solstices to their correct and verifiable dates that could weather the effects of axial precession for thousands of years. It is on this merit that the Gregorian calendar gradually came to be accepted across the world. Yet, at the same time, the reform project piloted by the Catholic Church came in the late 16th century when its estrangement from the Greek Orthodox Church was complete in the East, whereas in the West, the Protestant revolt was underway.
The Catholic nations accepted the calendrical reforms as a religious injunction from Pope Gregory XIII, even though it meant obliterating ten consecutive days in October from the calendar of 1582. The protestant nations were tardy to accept the change—England did so in 1752—whereas the Eastern Orthodox nations were slower still. Russia accepted the Gregorian calendar in 1918 following the revolution, which entailed an official suppression of the Church, whereas Greece, identified with the Greek Orthodox Church, accepted the change in 1923.
Dogma is not specific to religious orders; it can infect thoroughbred scientists as well. Tycho Brahe (1546-1601), despite his reverence for Nicolaus Copernicus (1473-1543), could not fully accept his heliocentric model. He created an admixture of geocentrism and heliocentricity, claiming that while the planets orbited the Sun, the Sun and Moon, in turn, revolves around the Earth. While Brahe’s geocentrism might be attributed to his Protestant lineage – Protestantism having rejected the heliocentricity extended by Catholic churchmen like Copernicus – Johannes Kepler (1571–1630), also a Protestant, demonstrated a more accurate understanding.
On reading Kepler’s Mystery of the Universe (1596), Brahe congratulated him, and invited the promising German physicist to Prague to collaborate with him. However, Brahe expressed regret that Kepler favoured the Copernican system over his own. “Everyone loves himself," Kepler noted in Latin in the margins of Brahe’s letter. In 1601 when Brahe passed away in Prague, while working on the Rudolphine Tables, he beseeched his young collaborator Kepler to complete them, “adding the hope that he would base them on his system of the world rather than Copernican" (J.G. Crowther, Six Great Astronomers, P.49).
Brahe was the last great European astronomer to work without a telescope. In contrast, Kepler, a contemporary of Galileo Galilei (1564–1642) and in contact with the Italian master, had the advantage of using the telescope. With his knowledge of physics, Kepler improved the Copernican model. He brought the Rudolphine Tables to completion only in 1627 at Ulm, a city in southwestern Germany, where Albert Einstein was later born in 1879. Kepler, while perfecting the heliocentric model, replaced the concentric circle of planetary orbits with ellipses, the simplest form of oval curves. He found it fitted very well if the Sun were placed not at the centre of the ellipse but at one of its foci (Six Great Astronomers, P.69).
The Gregorian reforms (1582) came four decades after Copernicus’ publication of De Revolutionibus Orium Ceolestium Libri VI (Six Books Concerning the Revolutions of Heavenly Spheres) in 1543. However, neither was the theory accepted by the Church then, nor it had anything to do with the reforms. Positional astronomy is independent of heliocentricity, and only the true length of the tropical solar year was critical to the reforms. This distinction was the sole factor differentiating the Julian calendar from the Gregorian.
The Julian calendar, instituted by Julius Caesar in 45 BC, considered the length of the tropical year as 365 days and 6 hours. Every fourth year was designated as a leap year, which was marked by intercalation of an extra day in the calendar. However, the natural tropical year is at least 11 minutes shorter than its value computed then. The corrected modern value of the tropical year is 365 years, 5 hours, 48 minutes, and 45.2 seconds (or 365.242190 days). The Julian year, while overshooting the natural year by over 11 minutes, made the equinoxes and solstices crawl through the calendar through its cumulative effect across the centuries.
The Church was no timekeeper, but the crawling of the equinoctial day affected the date of Easter observance. The determination of Easter, the principal movable festival of Christianity, had contributed to the growing chasm between Rome and Near Eastern churches since the 1st century AD. The Roman Church makes its date dependent on the equinox, the full moon, and Sunday, in that sequence. Thus, it was not for the sake of science, but religion, that the Church got interested in the question of calendar reforms. It was first flagged in the First Council of Nicaea in 325 AD. Little, however, was done over the ensuing one millennium to correct the diversion, which went on widening with time.
Disagreement over the true measure of the tropical year as well as the formula of intercalation kept calendar reforms in abeyance. This was despite the proposals advanced by Roger Bacon (1220-92), Pierre d’Ailly (1350-1425), and Nicolas de Cusa (1401-64) in different epochs. Nicolaus Copernicus contributed precious little to the debate, by declining the invitation of Pope Leo X in 1514 to join the Fifth Lateran Council (1512-17) to deliberate on the calendar question. In his book De Revolutionibus, he revealed that he declined the invitation since it was a blind pursuit to try reforming the calendar without determining the true length of the tropical year.
The Council of Trent (1545-1563), the longest in the history of ecumenical councils, led to the production of several works on calendar reforms. A notable example is the work by Petrus Pitatus, originally written in 1539. Among other proposals, Pitatus advocated the removal of 14 days from the calendar in one stroke to make the equinoxes coincide with their original dates in the Julian calendar. He also pleaded, informs J.D. North (1982), for making three of every four centennial years as normal years rather than leap years (Proceedings of the Vatican Conference to commemorate its 400th Anniversary 1582-1981, P.101).
The Gregorian reformation of the calendar in 1582, in principle, conformed to both ideas. The excess days were obliterated in one stroke, rather than gradual easing, though only to the extent of 11 days rather than 14.
However, the treatise that ultimately influenced Pope Gregory XIII (r. 1572–1585) was authored by Late Aloysius Lilius, a physician and astronomer from southern Italy. The manuscript was presented in 1576—the year of Aloisius’s death—by his younger brother Antonius, who was also an astronomer and one of the signatories of the nine-member Papal Commission that presented its report in September 1580. The other two astronomers who appended their signatures were Christophe Clavius and Ignazio Danti. The Papal Bull to promulgate the new calendar was issued on February 24, 1582. The reforms aimed at restoring the equinoctial day—as in the times of Nicaean Council—in 325 AD, and not to 44 BC, when the Julian calendar was notified.
The actual reform was implemented later that year. Ten days were removed from the calendar, re-designating 5 October as 15 October, making October 1582 a short month of 21 days and the year itself a short year of 355 days. The Gregorian reforms also recalibrated the rules for leap years. “In order to maintain in future a more exact correspondence between the tropical and the calendar year," notes Alexander Philip (1921), “it was provided that three out of four centurial years should be common years instead of leap years as in Julian calendar; only those centurial years divisible by 400 without remainder were retained as leap years" (The Calendar: Its History, Structure and Improvement, P.21-22).
Thus, post-reform, while 1600 AD was a leap year, the years 1700 AD, 1800 AD and 1900 AD were not. However, 2000 AD was once again a leap year.
The Catholic nations accepted the reforms very soon. Italy, Poland, Portugal and Spain implemented the calendar in 1582, whereas France and the Catholic Netherlands followed in 1583. The Protestant states of Europe, chiefly on the advice of philosopher Leibniz, fell in line. Britain adopted the Gregorian calendar in 1752 following the enactment of the Calendar (New Style) Act 1750. The countries dominated by the Eastern Orthodox Church were slow to respond. “Everyone loves himself," as Kepler noted!
Russia had to adopt the Gregorian calendar by officially banning the Orthodox Church in 1918. However, even as the entire world, transcending religious barriers, accepted the reformed tropical calendar, grounded in reason and mathematics, segments of the Eastern Orthodox Church continue to adhere to the Julian calendar for liturgical purposes, despite their nations having long migrated to the Gregorian system. Ukraine is the latest frontier to be breached.
The writer is author of the book ‘The Microphone Men: How Orators Created a Modern India’ (2019) and an independent researcher based in New Delhi. Views expressed in the above piece are personal and solely that of the author. They do not necessarily reflect News18’s views.
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