Start year and End year specify the range of years you're interested in. For example, if you enter , and then after you click on 'Submit' the output is: 1st January CE is a Monday. The following calendar years in the range through are identical to 6: 6: 6: 6: 6: 6: 6: The numbers in parentheses a:b give the number of years since the previous year and the number of days from one 1st January to the 1st January of the next year of the same type.
As another example, if you enter , and then after you click on 'Submit' the output is: 1st January CE is a Friday. The following calendar years in the range through are identical to Since 1st January of any given year occurs on one of seven weekdays, and a year is either a leap year or not, there are fourteen possible calendar years.
As the results above show, the calendar years do not proceed in a regular fashion. This is because a year consists either of 52 weeks plus 1 day or in a leap year 52 weeks plus 2 days, so the day of the week of the 1st January of the next year is either one or two days later in the week.
And when a year with 1st January on the same day of the week comes around again it may or may not be a leap year. The possible numbers of days elapsed from the 1st of January to the 1st of January of the next year of the same type is always one of: 2, 6 years , 4, 11 years , 4, 12 years , 10, 28 years and 14, 40 years. Thus to use that nice wall calendar again you'll have to wait at least six years and at most forty years.
Each of these numbers of days is a multiple of 7 because the 1sts January of years in a sequence of years of the same type always occur on the same day of the week.
It's curious that 1, happens to be the number of days in four successive Gregorian years, and here it emerges again as a possible number of weeks between successive 1sts January in years of the same type. A coincidence? Since the Gregorian calendar follows the Julian pattern, except for some century years it's bound to occur for leap years. Like many other calendars, the Gregorian calendar is based on the movements and positioning of the sun.
Each year is divided into 12 months, which are then divided into between 28 and 31 days. However, the Gregorian calendar is not the only calendar, and it's certainly not the first one people have used in history. Before the advent of this calendar type, much of Western civilization adhered to the Julian calendar , which was proposed by Julius Caesar and used by the Roman Empire.
Before that, different groups used the Roman calendar and the Athenian calendar. Notably, nearly every prominent ancient civilization had its own calendar, and these various calendars didn't adhere to the same rules. One of the reasons why the Gregorian calendar has continued to find usage worldwide despite its creation and implementation is that it is a unifying, easy-to-understand concept.
However, some cultures and groups around the world don't recognize the Gregorian calendar or its structure. Instead, they continue to use the calendars their ancestors created.
While patterns are commonly found in other types of date-keeping systems, they don't repeat in the same manner or frequency as they do with the Gregorian calendar. The Gregorian calendar repeats itself in year cycles. However, some patterns may repeat as few as every six years. Generally, leap years experience the lengthiest pauses between similar day-week patterns 28 years , while non-leap years may repeat every six or 11 years.
During this century, the pattern will hold to an pattern. This means that a calendar will repeat itself in 11 years. Eleven years after that, it will repeat again.
Six years from that date, it will once again become applicable. For example, take a look at the year The first day of January was a Monday. Eleven years prior, in , the new year's first day had also been a Monday. The same was true of The next Monday-based New Year's Day after came in Thus, the cycle before had been , which left the six-year portion of the cycle to follow, indicating that the next repetition would occur in six years later.
For example, the year will repeat itself again six years from now in It will also repeat in , and Other repeating calendars in the upcoming future are reusable as follows:. As calendar years repeat themselves, you save the calendars you love. These calendars will be available to reuse in the future. Keep track of the calendar times, specifically the dates and days of the week, to know when you can reuse the calendars.
To help reuse calendars, try to resist filling in the boxes with notes.
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