The Gregorian Calendar is a calendar which was introduced in 1582 under the direction of Pope Gregory XIII. It replaced the Julian Calendar which had been devised and introduced to Europe sixteen centuries earlier under the guidance of Julius Caesar. Both calendars were actually quite similar, but the Julian Calendar was established in such a way that it calculated leap years slightly incorrectly and over a period of over 1,600 years this had amounted to the loss of approximately 10 days. The Papacy decided to reform this by introducing the new calendar in line with developing scientific knowledge in early modern Europe. The Gregorian Calendar was quickly adopted by the Roman Catholic powers across Europe and in the decades that followed so too did many Protestant states, however some were obstinate in refusing to accept the Papal-sanctioned calendar. Protestant Britain, for instance, did not adopt it until 1752. Today the Gregorian Calendar is used extensively by nearly every country on earth in either an official or unofficial capacity to calculate the year, the date and the passage of time.[1]
Gregorian calendar historical context
In the sixteenth century scientific knowledge was expanding across Europe pursuant from extensive observations of the celestial spheres and the solar system. As this occurred more accurate accounts of the movement of the planets and the length of time which it took Earth to rotate around the Sun were introduced. With this developing knowledge, it was realized that the Julian Calendar, which had been created by the Romans under the guidance of Julius Caesar back in the mid-first century BCE, was slightly incorrect in the manner in which it calculated the equinoxes and leap years. This error resulted in the loss of a fraction of a day every year. Over a period of sixteen centuries it had resulted in the loss of approximately ten days. As a result, Pope Gregory XIII ordered the revision of the calendar in line with some changes which the Calabrian doctor, Aloysius Lilio, had made in the late 1570s. The result was the Gregorian Calendar which was issued through the Papal Bull, Inter Gravissimas, in 1582.[2]
The calendar was not accepted unequivocally across Europe when it was first introduced. This was the era of the Protestant Reformation and the Wars of Religion in Europe and many Protestant states viewed Gregory’s actions, quite correctly, as a piece of Papal propaganda. Consequently many refused to accept the Gregorian reforms when they were initially introduced. These included the Dutch Republic, which did not adopt the Gregorian Calendar until 1700, the same year that Prussia and the Kingdom of Denmark-Norway did so. Britain, and with it its extensive colonies in North America, the Caribbean and further afield, did not formally adopt it until 1752. Countries where the Eastern Orthodox Church was dominant were even more recalcitrant. For instance, Greece did not adopt the Gregorian Calendar until 1923. By then many non-European nations had already implemented it. Japan, Korea and China did so in 1873, 1896 and 1912 respectively as part of their efforts to modernize their nations along western lines.[3]
Details of the Gregorian calendar
The Gregorian Calendar is familiar to nearly everyone these days, as it forms the basis for the calendars used in virtually every country worldwide, at least concerning civil matters. It is a solar calendar which consists of twelve months: January, February, March, April, May, June, July, August, September, October, November and December. These are virtually unchanged from the earlier Julian Calendar which it was designed to replace. For instance, March is still known as such under the Gregorian Calendar after its name, Martius, from the Roman God of War, Mars. July is still known as such after being given this name in Roman times in honor of Julius Caesar, while August continued to be known as such under the Gregorian system after first being given this name to honor Emperor Caesar Augustus in Roman times. April remains known as this from the Latin Aperio, meaning ‘to open’ as in for the first buds of spring opening.[4]
Where the Gregorian Calendar differed considerably from the Julian Calendar was in calculating the year from the supposed birth of Jesus Christ, whereas the Romans had calculated the year in the Julian Calendar from 753 BCE or Ab Urbe Condita, from the alleged founding of the city of Rome by Romulus and Remus that year. However, this change in the year calculation had been made centuries before the introduction of the Gregorian Calendar by the leaders of the early Christian church. Consequently, the Gregorian Calendar was very much a continuation of the calendar system which had existed prior to the sixteenth century, but with slight alterations to take account of modern scientific knowledge.[5]
The major difference in the Gregorian Calendar is that it accurately calculated for the first time that the year consisted of 365.242 days rather than 365.25, as the Julian Calendar had calculated. This slight discrepancy had led to a minor error accumulating over centuries and leading to the Julian Calendar gaining a day every 130 or so years. In order to remedy this, the Gregorian Calendar involves skipping a leap year once every 130 or so years and so remains scientifically accurate over the centuries in so far as the seasons remain fixed.[6]
Relevance of the Gregorian calendar in modern times
The Gregorian Calendar is employed virtually worldwide today. This is for a number of very clear reasons. Firstly, it is a scientifically accurate solar calendar, the first which was produced and one which has subsequently not needed to be replaced since the late sixteenth century. Secondly, because of the manner in which European nations colonized and took over virtually every part of the world between the seventeenth and nineteenth centuries, they were able to introduced this calendar and it became a kind of universal calendar in much the same way that English has become something of a lingua franca in the modern world owing to the extent of the British Empire in early modern and modern times. Consequently, while many countries today still use alternative calendars to calculate the religious year or to calculate the year in which history began, the Gregorian Calendar is used in one form or another in virtually every country in the world.[7]
Explore more about the Gregorian calendar
- Understanding Historical Dates and Calendars for Historical Research by James Tanner, article on the MyHeritage Knowledge Base
- Understanding Dates: Five Common Mistakes to Avoid on the MyHeritage Blog
References
- ↑ https://www.timeanddate.com/calendar/gregorian-calendar.html
- ↑ https://www.jstor.org/stable/24966597
- ↑ https://www.nottingham.ac.uk/manuscriptsandspecialcollections/researchguidance/datingdocuments/juliangregorian.aspx
- ↑ https://www.almanac.com/how-did-months-get-their-names
- ↑ https://www.theguardian.com/theguardian/2010/jan/13/how-ancient-rome-counted-years
- ↑ https://airandspace.si.edu/stories/editorial/science-leap-year
- ↑ https://www.calendar.com/blog/gregorian-calendar-facts/