Why while most of the world is living in year 2015, it is year 2129 or 4713 (depending on the region and culture) in the Chinese calendar, year 2558 in the Thai calendar, year 5775 in the Hebrew calendar and year 2071 in the Hindi calendar? Yes, indeed, it is the systems to divide and count the time – that is responsible for the differences!
As a side note, let us remind that the spelling of the word calendar is commonly mistaken with calender, which stands for a person or machine involved in the business where cloth, paper, etc., is pressed under rollers for the purpose of smoothing or glazing.
Our word calendar originates from the Latin calendarium “account book” which was named after calendae – the name of the first day of the Roman month, the day when usually debts felt due and accounts were reckoned and marked down in the calendarium.
The first day of the month in the Roman Empire, on its end, was named after the verb calare “to announce solemnly, call out,” as the priests did in proclaiming the new moon that marked the beginning of a new month. Obviously, the Roman calendar, based on the Greek, was a lunar one. The time between new moons averages 29.5 days its months were constructed to be either hollow (29 days) or full (30 days).
The reform of the Roman calendar – the Julian calendar with the standard 365 days, divided into 12 months and a leap day added every four years – was introduced by Julius Caesar in 46 BC and was the predominant calendar in the after Roman world, most of Europe, and in European settlements in the Americas and elsewhere, until the Gregorian reform of 1582.
The earliest written references in the English language came before the reform, with the first one from circa 1250, The Chronicle of Britain where the English priest Layamon among from acknowledging Caesar’s bravery and wisdom also highlights his establishment of the calendar along with many of the Roman laws.
Caesar’s wisdom set the length of the year to 365.25 days, but as the tropical year was indeed a few minutes shorter, the Caesar’s calendar ended up adding about three days every four centuries. In 1582, as mentioned above, the Gregorian reform refinement adjusted the length of the year to 365.2425 days and gradually replaced the Caeser’s calendar in all Roman Catholic countries by dropping days, Thursday, October 4, 1582 was followed by Friday, October 15.
Consequently, the Julian calendar, referred to as Old Style (O.S) is currently 13 days behind the Gregorian calendar, the New Style (N.S.).
During the 18th century most European protestant countries, along with Great Britain and the American colonies accepted the reform, followed by Russia and the Eastern Orthodox countries in the 20th century.
In other parts of the world the new system was labelled the Christian Calendar and its name created resistance among Hindus, Buddhists, Taoists and other religion groups which kept to their calendars and hence today we count the time differently, yet celebrate it together.