The Gregorian calendar can, for certain purposes, be extended backwards to dates preceding its official introduction, producing the proleptic Gregorian Calendar. However, this proleptic calendar should be used with great caution. For ordinary purposes, the dates of events occurring prior to 15 October 1582 are generally shown as they appeared in the Julian calendar, and not converted into their Gregorian equivalents. However, events occurring in countries where the Gregorian calendar was introduced later than 4 October 1 ...

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Gregorian calendar, Gregorian calendar - History, Gregorian calendar - Invention, Gregorian calendar - Beginning of the year, Gregorian calendar - Adoption outside of Roman Catholic nations, Gregorian calendar - Proleptic Gregorian calendar, Gregorian calendar - Confusion with British vs. American usage, Gregorian calendar - Difference between Gregorian and Julian calendar dates, Gregorian calendar - Months of the year, Gregorian calendar - Accuracy, Gregorian calendar - Calendar seasonal error, Gregorian calendar - Numerical facts, Gregorian calendar - Number of leap years starting on a given day of the week, Gregorian calendar - Days of the week, Gregorian calendar - Reference

Read more here: » Gregorian calendar: Encyclopedia II - Gregorian calendar - Proleptic Gregorian calendar

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Gregorian calendar, Gregorian calendar - History, Gregorian calendar - Invention, Gregorian calendar - Beginning of the year, Gregorian calendar - Adoption outside of Roman Catholic nations, Gregorian calendar - Proleptic Gregorian calendar, Gregorian calendar - Confusion with British vs. American usage, Gregorian calendar - Difference between Gregorian and Julian calendar dates, Gregorian calendar - Months of the year, Gregorian calendar - Accuracy, Gregorian calendar - Calendar seasonal error, Gregorian calendar - Numerical facts, Gregorian calendar - Number of leap years starting on a given day of the week, Gregorian calendar - Days of the week, Gregorian calendar - Reference

Read more here: » Gregorian calendar: Encyclopedia II - Gregorian calendar - Calendar seasonal error

The Gregorian calendar improves the approximation made by the Julian calendar by skipping 3 Julian leap days in every 400 years, giving an average year of 365.2425 mean solar days long, which has an error of about 1 day per 3300 years with respect to the mean tropical year of 365.2422 days but less than half this error with respect to the vernal equinox year of 365.2424 days. Both are substantially more accurate than the 1 day in 128 years error of ...

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Gregorian calendar, Gregorian calendar - History, Gregorian calendar - Invention, Gregorian calendar - Beginning of the year, Gregorian calendar - Adoption outside of Roman Catholic nations, Gregorian calendar - Proleptic Gregorian calendar, Gregorian calendar - Confusion with British vs. American usage, Gregorian calendar - Difference between Gregorian and Julian calendar dates, Gregorian calendar - Months of the year, Gregorian calendar - Accuracy, Gregorian calendar - Calendar seasonal error, Gregorian calendar - Numerical facts, Gregorian calendar - Number of leap years starting on a given day of the week, Gregorian calendar - Days of the week, Gregorian calendar - Reference

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August 11 is the 223rd day of the year (224th in leap years) in the Gregorian Calendar. There are 142 days remaining. August 11 - Events. 3114 BC - On this date in the proleptic Gregorian calendar begins our current era in the Maya Long Count Calendar. 480 BC - Persians under Xerxes defeat Spartans under King Leonidas in the Battle of Thermopylae. The Spartans fought to the last man. 480 BC - The Persian and Greek fleets also fight the indecisive Battle ...

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August 11 - Events August 11 - Births August 11 - Deaths August 11 - Holidays and observances

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Centuries: 1st century BC - 1st century - 2nd century Decades: 40s BC 30s BC 20s BC 10s BC 0s BC - 0s - 10s 20s 30s 40s 50s Years: 1 2 3 4 5 6 7 8 9 Because of the nonexistence of the "year 0", this "decade" and its predecessor have only nine years each. (Year 0 does not exist in either the proleptic Gregorian calendar or Julian calendar) 0s - Events and trends. 0s - Significant people. Caesar Augustus, Roman Emperor (27 BC - 14 AD).Including:

0s - Events and trends 0s - Significant people

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They are not in the proleptic Gregorian calendar. ——— Image courtesy of chinapage.com Emperor Tang Wuzong (武宗 814-846), born Li Yan, was a later emperor of the Tang dynasty of China. He reigned from 840 to 846. Wuzong is remembered mainly for the religious persecution that occurred during his reign. Wuzong ascended to the throne in a time of economic and political crisis. Military eunuchs had controlled the government for some time. They had put the previous emperor, Wenzong, u ...

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Centuries: 2nd century BC - 1st century BC - 1st century Decades: 50s BC 40s BC 30s BC 20s BC 10s BC - 0s BC - 0s 10s 20s 30s 40s Years: 9 BC 8 BC 7 BC 6 BC 5 BC 4 BC 3 BC 2 BC 1 BC Because of the nonexistence of the "year 0", this "decade" and its successor have only nine years each. (Year 0 does not exist in either the proleptic Gregorian calendar or Julian calendar) 0s BC - Events and trends. circa 4 BC - Jesus is born in Bethlehem. 0 ...

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0s BC - Events and trends 0s BC - Significant people

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The Gregorian calendar is the calendar that is used nearly everywhere in the world. A modification of the Julian calendar, it was first proposed by the Neapolitan doctor Aloysius Lilius, and was decreed by Pope Gregory XIII, for whom it was named, on 24 February 1582 (Note: The papal bull Inter gravissimas was signed in the year 1581 for unknown reasons, but printed on 1 March 1582. Although the use of the date 1581 is often attributed to the supposed adoption by the papacy of a reckoning by which the year began on 25 March, other contemporaneous papal bulls have years that do not agree with March years, let alo ...

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Gregorian calendar - History
Gregorian calendar - Invention Gregorian calendar - Beginning of the year Gregorian calendar - Adoption outside of Roman Catholic nations
Gregorian calendar - Proleptic Gregorian calendar Gregorian calendar - Confusion with British vs. American usage Gregorian calendar - Difference between Gregorian and Julian calendar dates Gregorian calendar - Months of the year Gregorian calendar - Accuracy Gregorian calendar - Calendar seasonal error Gregorian calendar - Numerical facts Gregorian calendar - Number of leap years starting on a given day of the week Gregorian calendar - Days of the week Gregorian calendar - Reference

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August 12 is the 224th day of the year (225th in leap years) in the Gregorian Calendar. There are 141 days remaining. It is the peak of the Perseid meteor shower. It is also known as the "Glorious Twelfth" in the UK, as it marks the traditional start of the grouse shooting season. August 12 - Events. 490 BC - the Battle of Marathon, in which Athens defeated an invasion army of Persians, may have been fought on this date in the proleptic Julian calendar - but see 12 Septe ...

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August 12 - Events August 12 - Births August 12 - Deaths August 12 - Holidays and observations

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Gregorian calendar - Invention. The motivation of the Catholic Church in adjusting the calendar was to have Easter celebrated at the time that they thought had been agreed to at the First Council of Nicaea in 325. Although a canon of the council implies that all churches used the same Easter, they did not. The Church of Alexandria celebrated Easter on the Sunday after the 14th day of the Moon that falls on or after the vernal equinox, which they placed on 21 March. However, the Church of Rome still regarded 25 Ma ...

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Gregorian calendar, Gregorian calendar - History, Gregorian calendar - Invention, Gregorian calendar - Beginning of the year, Gregorian calendar - Adoption outside of Roman Catholic nations, Gregorian calendar - Proleptic Gregorian calendar, Gregorian calendar - Confusion with British vs. American usage, Gregorian calendar - Difference between Gregorian and Julian calendar dates, Gregorian calendar - Months of the year, Gregorian calendar - Accuracy, Gregorian calendar - Calendar seasonal error, Gregorian calendar - Numerical facts, Gregorian calendar - Number of leap years starting on a given day of the week, Gregorian calendar - Days of the week, Gregorian calendar - Reference

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January 1 of any year whose number is a multiple of 400 is a Saturday. From this you can work out the day of the week of any date. See also: Days of the week Calculating the day of the week ...

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Gregorian calendar, Gregorian calendar - History, Gregorian calendar - Invention, Gregorian calendar - Beginning of the year, Gregorian calendar - Adoption outside of Roman Catholic nations, Gregorian calendar - Proleptic Gregorian calendar, Gregorian calendar - Confusion with British vs. American usage, Gregorian calendar - Difference between Gregorian and Julian calendar dates, Gregorian calendar - Months of the year, Gregorian calendar - Accuracy, Gregorian calendar - Calendar seasonal error, Gregorian calendar - Numerical facts, Gregorian calendar - Number of leap years starting on a given day of the week, Gregorian calendar - Days of the week, Gregorian calendar - Reference

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Dates of events in Britain prior to 1752 are usually now shown in their original Old Style form, whereas dates of events in (then British) America prior to 1752 are usually now shown in the New Style form. For example, Shakespeare died on 23 April (OS), and it is rare to see this converted to 3 May (NS). But while George Washington was born on 11 February (OS), his birthday is now celebrated on 22 February (N ...

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Gregorian calendar, Gregorian calendar - History, Gregorian calendar - Invention, Gregorian calendar - Beginning of the year, Gregorian calendar - Adoption outside of Roman Catholic nations, Gregorian calendar - Proleptic Gregorian calendar, Gregorian calendar - Confusion with British vs. American usage, Gregorian calendar - Difference between Gregorian and Julian calendar dates, Gregorian calendar - Months of the year, Gregorian calendar - Accuracy, Gregorian calendar - Calendar seasonal error, Gregorian calendar - Numerical facts, Gregorian calendar - Number of leap years starting on a given day of the week, Gregorian calendar - Days of the week, Gregorian calendar - Reference

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When leap years and common years are taken into account, there are a total of 14 possible Gregorian calendars. When different dates of Easter are also taken into account, there are a total of 70 possible Gregorian calendars. An average year is 365.2425 days = 52.1775 weeks = 8,765.82 hours = 525,949.2 minutes = 31,556,952 seconds. A common year is 365 days = 8,760 hours = 525,600 minutes = 31,536,000 seconds. A leap year is 366 days = 8,784 hours = 527,040 minutes = 31,622,400 seconds. (Some years may also contain one or two leap seconds which can be positive or negative.) See als ...

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Gregorian calendar, Gregorian calendar - History, Gregorian calendar - Invention, Gregorian calendar - Beginning of the year, Gregorian calendar - Adoption outside of Roman Catholic nations, Gregorian calendar - Proleptic Gregorian calendar, Gregorian calendar - Confusion with British vs. American usage, Gregorian calendar - Difference between Gregorian and Julian calendar dates, Gregorian calendar - Months of the year, Gregorian calendar - Accuracy, Gregorian calendar - Calendar seasonal error, Gregorian calendar - Numerical facts, Gregorian calendar - Number of leap years starting on a given day of the week, Gregorian calendar - Days of the week, Gregorian calendar - Reference

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The Gregorian calendar's year is divided into 12 months: English speakers sometimes remember the number of days in each month by the use of the traditional mnemonic verse: Thirty days hath September / April, June and November / All the rest have thirty-one / Excepting February alone / Which has but twenty-eight, in fine / Till leap year gives it twenty-nine. Alternate endings are: Which has eight and a score / Until leap year gives it one day more, or Which hath twenty-eight days clear / And twenty-nine in each leap year. or When ...

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Gregorian calendar, Gregorian calendar - History, Gregorian calendar - Invention, Gregorian calendar - Beginning of the year, Gregorian calendar - Adoption outside of Roman Catholic nations, Gregorian calendar - Proleptic Gregorian calendar, Gregorian calendar - Confusion with British vs. American usage, Gregorian calendar - Difference between Gregorian and Julian calendar dates, Gregorian calendar - Months of the year, Gregorian calendar - Accuracy, Gregorian calendar - Calendar seasonal error, Gregorian calendar - Numerical facts, Gregorian calendar - Number of leap years starting on a given day of the week, Gregorian calendar - Days of the week, Gregorian calendar - Reference

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Because there are 97 leap years in every 400 in the Gregorian Calendar, there should, in each "cycle", be either 13 or 14 leap years starting on each day of the week. However, the effects of the "common" centennial years (1700, 1800, 1900, 2100, 2200 etc.) cause major alterations. This is because the absence of an extra day in such years causes the following leap year (1704, 1804, 1904, 2104 etc.) to start on the same day of the week as the leap year twelve years before (1692, 1792, 1892, 2092 etc.). Similarly, the leap year ei ...

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Gregorian calendar, Gregorian calendar - History, Gregorian calendar - Invention, Gregorian calendar - Beginning of the year, Gregorian calendar - Adoption outside of Roman Catholic nations, Gregorian calendar - Proleptic Gregorian calendar, Gregorian calendar - Confusion with British vs. American usage, Gregorian calendar - Difference between Gregorian and Julian calendar dates, Gregorian calendar - Months of the year, Gregorian calendar - Accuracy, Gregorian calendar - Calendar seasonal error, Gregorian calendar - Numerical facts, Gregorian calendar - Number of leap years starting on a given day of the week, Gregorian calendar - Days of the week, Gregorian calendar - Reference

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The standard uses the Gregorian calendar, already the de facto standard of international trade. The standard acknowledges that other calendars may be used, such as the Julian calendar used by astronomers. It suggests that senders and receivers should explicitly agree when another calendar is used with the standard's notation. Dates are otherwise assumed to be Gregorian. In principle, dates should usually be converted to the proleptic Gregorian cal ...

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ISO 8601, ISO 8601 - History of the standard, ISO 8601 - General principles, ISO 8601 - Dates, ISO 8601 - Calendar date, ISO 8601 - Week dates, ISO 8601 - Ordinal dates, ISO 8601 - Further details about dates, ISO 8601 - Times, ISO 8601 - Time zones, ISO 8601 - Combined representations, ISO 8601 - Duration, ISO 8601 - Time interval, ISO 8601 - Repeating intervals, ISO 8601 - Usage

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The ordinary year in the previous Roman calendar consisted of 12 months, for a total of 355 days. In addition, an intercalary month, the Mensis Intercalaris, was sometimes inserted between February and March. This intercalary month was formed by inserting 22 days before the last five days of February, creating a 27-day month. It began after a truncated February having 23 or 24 days, so that it had the effect of adding 22 or 23 days to t ...

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Julian calendar, Julian calendar - From Roman to Julian, Julian calendar - Leap years error, Julian calendar - Naming of the months, Julian calendar - Lengths of the months, Julian calendar - Year numbering, Julian calendar - From Julian to Gregorian

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Despite the new calendar being much simpler than the Roman calendar, the pontifices apparently misunderstood the algorithm. They added a leap day every three years, instead of every four years. According to Macrobius, the error was the result of counting inclusively, so that the four year cycle was considered as including both the first and fourth years. This resulted in too many leap days. Caesar Augustus remedied this discrepancy by restoring the correct frequency after 36 years of this mistake. He also ski ...

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Julian calendar, Julian calendar - From Roman to Julian, Julian calendar - Leap years error, Julian calendar - Naming of the months, Julian calendar - Lengths of the months, Julian calendar - Year numbering, Julian calendar - From Julian to Gregorian

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The epoch (starting point or first day of the first year) of the current era of Hindu calendar (both solar and lunisolar) is BCE 3102 January 23 on the proleptic Gregorian calendar (i.e. the Gregorian calendar extended back in time before its promulgation from 1582 October 15). Both the solar and lunisolar calendars started on this date. After that, each year is labeled by the number of years elapsed since the epoch. This is a unique feature of the Hindu calendar. All other systems use the current ordinal number of the year as ...

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Hindu calendar, Hindu calendar - Basic structure, Hindu calendar - Day, Hindu calendar - Tithi, Hindu calendar - Vaasara, Hindu calendar - Nakshatra, Hindu calendar - Yoga, Hindu calendar - Karana, Hindu calendar - Month and year of the solar calendar, Hindu calendar - Months of the lunisolar calendar, Hindu calendar - Naming lunar months, Hindu calendar - Religious observances in case of extra and lost months, Hindu calendar - Year of the lunisolar calendar, Hindu calendar - Another kind of lunisolar calendar, Hindu calendar - Correspondence of the lunisolar calendar to the solar calendar, Hindu calendar - Year numbering, Hindu calendar - Year names, Hindu calendar - Eras, Hindu calendar - History

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Immediately after the Julian reform, the twelve months of the Roman calendar were named Ianuarius, Februarius, Martius, Aprilis, Maius, Iunius, Quintilis, Sextilis, September, October, November, and December, just as they were before the reform. Their lengths were set to their modern values. The old intercalary month, the Mensis Intercalaris, was abolished and replaced with a single intercalary day at the same point (i.e. five days before the end of Februarius). The first month of the year ...

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Julian calendar, Julian calendar - From Roman to Julian, Julian calendar - Leap years error, Julian calendar - Naming of the months, Julian calendar - Lengths of the months, Julian calendar - Year numbering, Julian calendar - From Julian to Gregorian

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