785:, quite popular among economists between the World Wars, are proposals that start each year on a Sunday. The 364 days within the week system form 52 weeks of 7 days. The World Calendar has every quarter beginning on the same day of the week. In the World Calendar, the 365th and 366th day are considered holidays and named Worlds Day and Leap Year Day. These "off-calendar" days stand outside the seven-day week and caused some religious groups to strongly oppose adoption of the World Calendar. Such concerns helped prevent the World Calendar from being adopted. Supporters of the World Calendar, however, argue that the religious groups' opposition overlooked every individual's right to celebrate these holidays as extra days of worship, or
578:
3017:
504:
159:
38:
3007:
271:, are secondary, convenient features of a calendar. Most cultures adopt a primary dating system, but different cultures have always needed to align multiple calendars with each other, either because they coexisted in the same space (e.g. secular and religious groups with different demands) or had established trading relations.
413:
revolutions of a planet and its satellite(s) can be phase-locked – for example the same side of the moon always faces us – but this has not operated to lock together the lengths of the Earth's year, day and month.) Such remainders could accumulate from one period to the next, thereby driving the cycles out of synchronization.
819:, months are discarded altogether; instead, the year is divided into four seasons of 13 weeks each. An extra day (two days during leap year) is added to the calendar that is not assigned a day of the week in order to perennialize the calendar. The same calendar of 91 days is used for each season of every year.
435:
to remedy this defect. Identifying the lunar cycle month requires straightforward observation of the Moon on a clear night. However, identifying seasonal cycles requires much more methodical observation of stars or a device to track solar day-to-day progression, such as that established at places like
1108:
Since the beginning of the 21st century, there is a trend within the Muslim communities of North
America and Europe to substitute a lunar calendar based on calculations for the traditional Islamic method of monthly observation of the new moon to declare the beginning of the new month in each country
970:
every 3 or 2 years with 30 or 31 days. 60 years together are called a cycle. It uses a leap cycle which has equal number of days, weeks, months, years and cycles. 2498258 days, 356894 weeks, 84599 months, 6840 years and 114 cycles nearly all equal each other. It is called an era, although time isn't
535:
made 46 BC 445 days long and replaced the intercalary month with an intercalary day to be inserted within
February every four years. This produced a noticeably more accurate calendar, but it had an average year length of 365 days and six hours (365.25 days), which had the effect of adding about
434:
An obvious disadvantage of the lunisolar method of inserting a whole extra month is the large irregularity of the length of the year from one to the next. The simplicity of a lunar calendar has always been outweighed by its inability to track the seasons, and a solar calendar is used in conjunction
811:
Some calendars have quarters of regularly patterned uneven months e.g., a 35-day (five-week) month and a pair of 28-day (four-week) months, with a leap week appended to the final month when needed. The Common Civil
Calendar and Time calendar has months of 30 and 31 days, but inserts a leap week in
451:
over 2500 years, most of which were intended to better fit the calendar months to astronomical lunations and to more accurately add the extra month so that the regular months maintain their proper seasonal positions, even though each seasonal marker can occur anywhere within its month. There have
878:
as reformed by Julius Caesar do not follow any apparent logic systematically. Many reform proposals seek to make the pattern more uniform. When keeping the traditional dozen months and the close approximation of a solar year, this usually yields four equal quarters of three months each where one
412:
The fundamental problems of the calendar are that the astronomical year has neither a whole number of days nor a whole number of lunar months; neither does the lunar month have a whole number of days: in each case there are fractions "left over". (In some physical circumstances the rotations and
585:
This reform took a few centuries to spread through the nations that used the Julian calendar, although the
Russian church year still uses the Julian calendar. Those nations that adopted this calendar on or after 1700, had to drop more than ten days: Great Britain, for instance, dropped eleven.
739:
Most plans evolve around the solar year of a little more than 365 days. This number does not divide well by seven or twelve, which are the traditional numbers of days per week and months per year respectively. The nearby numbers 360, 364 and 366 are divisible in better ways. There are also
304:) or whether the design in use then and there shall be respected. Calendar schisms happen if not all cultures that adopted a common calendar system before perform a calendar reform at the same time. If date identifiers are similar but different, confusion and mistakes are unavoidable.
1277:
1000:
Calendar proposals that introduce a thirteenth month or change the Julian-Gregorian system of months often also propose new names for these months. New names have also been proposed for days out of the week cycle (e.g., 365th and leap) and weeks out of the month cycle.
899:
Some calendar reformers seek to equalize the length of each month in the year. This is often accomplished by creating a calendar that has 13 months of 4 weeks (28 days) each, making 364 days. The earliest known proposal of this type was the
Georgian Calendar (1745) by
609:
days: these remainders were chosen to delay as much as possible the first year (after the year of 1923) that this calendar would disagree with the
Gregorian calendar, which occurs in until 2800. It was adopted by some Eastern Orthodox Churches, under the names
769:
Proposals mainly differ in their selection of a leap rule, placing of the leap item (usually middle or end of the year), in the start day of the week and year, in the number (12 or 13) and size of months and in connected naming; some are compatible to the
766:. Leap week calendars add a leap week of seven days to the calendar every five or six years to keep the calendar roughly in step with the tropical year. They have years of either 364 days (52 weeks) or 371 days (53 weeks), thus preserving the 7-day week.
1285:
660:, which was mainly based upon concerns of religious groups about the proposed days that would be outside the seven-day week cycle ("blank days") and thus disrupt having a sabbath every seven days. Independently the
420:. This means occasionally adding an extra day, week, or month into the cycle. An alternative approach is to ignore the mismatch and simply let the cycles continue to drift apart. The general approaches include:
1012:) or leaders of vanished empires (July and August from the first Caesars), or ordinals that got out of synchronization (September through December, originally seventh through tenth, now ninth through twelfth).
804:, were created to solve this problem by having years of either 364 days (52 weeks) or 371 days (53 weeks), thus preserving the 7-day week. The 53-week calendar, used in government and in business for
633:
Since the papal reform in 1582, several proposals have been offered to make the
Gregorian calendar more useful or regular. Very few reforms have gained official acceptance. The rather different
1004:
Proposals to change the traditional month and weekday names are less frequent. The
Gregorian calendar obtains its names mostly from gods of historical religions (e.g., Thursday from Nordic
259:
in past, present and future by a specific date in order to record or organize social, religious, commercial or administrative events. Recurring periods that contain multiple days, such as
439:. After centuries of empirical observations, the theoretical aspects of calendar construction could become more refined, enabling predictions that identified the need for reform.
536:
three-quarters of an hour every four years. The effect accumulated from inception in 45 BC until by the 16th century the northward equinox was falling on March 10 or 11.
789:. This option, they reason, maintained the seven-day worship cycle for those who share that concern, while allowing benefits of a perennial calendar to be shared by all.
1020:
Comte's
Positivist calendar, for example, proposed naming the 13 months in his calendar after figures from religion, literature, philosophy and science. Similarly, the
754:
Many calendar reforms have offered solutions to make the
Gregorian calendar perennial. These reforms would make it easy to work out the day of the week of a particular
2602:
2249:
915:, was based on a 364-day year which included one or two "blank" days. Each of the 13 months had 28 days and exactly four weeks, and each started on a Monday. The
427:
The solar calendar, which fits artificial months into the year, adding an extra day into one month when needed, while ignoring the lunar cycle of new/full moons.
562:
So that the northward equinox would have the same date in the new Gregorian calendar as it had when the Council of Nicaea made recommendations in AD 325 (
1359:
Cook, Anna J. (1st August 2024) A Man Beyond Time: Moses B. Cotsworth's fight for the 13-month calendar, Independent Publishing Network ISBN 978-1-80517-720-3
2867:
891:
uses 4:5:4 weeks per month. They all result in 364 systematically distributed days and hence have to add either one extra and one leap day or a leap week.
1456:"A PROPOSED PLAN FOR AN INVARIABLE CALENDAR; Prof. L.A. Grosclaude Offers an Interesting Suggestion to Solve the Troubles of the Present Division of Days"
424:
The lunar calendar, which fits days into the cycle of lunar months, adding an extra day when needed, while ignoring the annual solar cycle of the seasons.
605:
that only centennial years that leave a remainder of 200 or 600 upon division by 900 would be leap years, decreasing the average year length to 365.24
464:
version of the Hindu calendar which changed the distribution of the days in each month to better match the length of time that the Sun spends in each
657:
1455:
297:
Some design changes, however, will yield date identifiers different from the previous design for some days, often in the distant past or future.
1736:
812:
the middle of the year, when needed, whereas its successor, the Hanke–Henry Permanent Calendar, moves the extra week to the end of the year.
401:. Most reforms for calendars have been to make them more accurate. This has happened to various lunar and lunisolar calendars, and also the
2394:
1124:
278:
cannot be altered without becoming a new design. If a proposed design is sufficiently close to the legacy one, i.e. compatible with it, a
1807:
2685:
1134:
1073:
884:
801:
1206:
1694:
1613:
1555:
1498:
1439:
242:
121:
2344:
176:
55:
982:
uses a more accurate leap cycle of 4366 months per 353-year cycle, with 130 leap years per cycle, and a progressively shorter
223:
102:
516:
includes a banner with the protest slogan against the Gregorian calendar: "Give us our Eleven days" (on floor at lower right)
180:
59:
195:
74:
381:
Historically, most calendar reforms have been made in order to synchronize the calendar with the astronomical year (either
1262:
The Gregorian Reform of the Calendar: Proceedings of the Vatican Conference to Commemorate its 400th Anniversary 1582–1982
758:, and would make changing calendars each year unnecessary. There are, roughly speaking, two options to achieve this goal:
311:
Whether and how days are grouped into subdivisions such as months and weeks, and days outside those subdivisions, if any.
2690:
2628:
2421:
1043:
1021:
959:
is a lunisolar calendar proposal which has 12 or 13 lunar months of 29 or 30 days a year, and begins each year near the
956:
916:
782:
717:
Solstices and equinoxes do not coincide with either the beginning of the Gregorian months or the midpoint of the months.
202:
81:
3041:
2528:
1856:
763:
696:
The year's four quarters (of three full months each) are not equal (being of 90/91, 91, 92 and 92 days respectively).
417:
559:
long. While this does not synchronize the years entirely, it would require a few thousand years to accumulate a day.
430:
The lunisolar calendar, which keeps both the lunar and solar cycles, adding an extra month into the year when needed.
2862:
2503:
2012:
1748:
845:
686:
637:
169:
48:
2632:
979:
661:
294:, where the start of the month is now derived from astronomical data rather than sightings by religious leaders.
209:
88:
2565:
2108:
2049:
1945:
1259:(1983). "The Civil Reception of the Gregorian Calendar". In Coyne, G. V.; Hoskin, M. A.; O., Pedersen (eds.).
547:: only centennial years evenly divisible by 400 are leap years. Thus, the years 1600, 2000, 2400 and 2800 are
2513:
2382:
1800:
1260:
1222:
1119:
611:
598:
191:
70:
2339:
1963:
1156:
512:
326:
664:
still tries to find a common rule for the date of Easter, which might be eased by a new common calendar.
626:
is currently used by most of the world. There is also an international standard describing the calendar,
456:, all intended to make the month a better match to the lunation and to make the year a better fit to the
2978:
2973:
2740:
1063:
901:
816:
2966:
1710:
Khalid Chraibi, The Reform of the Islamic Calendar: The Terms of the Debate, Tabsir.net, September 2012
590:
681:
Months are not equal in length, nor regularly distributed across the year, and so some people rely on
2847:
2730:
2555:
2463:
2081:
1975:
1891:
1571:
1543:
966:
The Meyer–Palmen Solilunar Calendar has 12 lunar months with 29 or 30 days plus a leap month called
300:
The calendar system must clarify whether dates are changed to the new design retroactively (using a
145:
system. The term sometimes is used instead for a proposal to switch to a different calendar design.
2929:
2700:
2662:
2498:
2448:
2298:
2276:
2271:
2217:
2147:
2115:
1654:
1053:
1048:
908:
577:
480:
was a reform of the preceding lunisolar calendar which completely divorced it from the solar year.
2436:
290:
due to problems between regions in China and practical changes in religious calendars such as the
3020:
2837:
2735:
2458:
2401:
2372:
2177:
2157:
1876:
1871:
1835:
1793:
1025:
947:
935:
920:
759:
749:
672:
623:
544:
406:
398:
1686:
1679:
1605:
1598:
1490:
1483:
1431:
1424:
1312:
Sanja Perovic (2012). "French Republican Calendar: Time, History and the Revolutionary Event".
3010:
2949:
2877:
2872:
2618:
2570:
2508:
2488:
2303:
2254:
2224:
2162:
2125:
2120:
2066:
2029:
1970:
1940:
1935:
1930:
1861:
1753:
1732:
1690:
1609:
1551:
1494:
1435:
1202:
1139:
1098:
649:
540:
469:
337:
216:
95:
2857:
2597:
2587:
2483:
2288:
2283:
2212:
2172:
2152:
2142:
2098:
2024:
2002:
1997:
1992:
1958:
1886:
1866:
1321:
1129:
828:
697:
690:
634:
477:
448:
291:
287:
3046:
2887:
2882:
2813:
2642:
2592:
2550:
2468:
2453:
2389:
2377:
2367:
2313:
2244:
2234:
2167:
2130:
2071:
2034:
1987:
1982:
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532:
507:
492:
473:
402:
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2441:
1726:
1547:
887:
follow this with 31:30:30 and 30:30:31 days per month, respectively. On the other hand,
2852:
2710:
2575:
2560:
2518:
2493:
2431:
2426:
2349:
2334:
2308:
2261:
2239:
2229:
2135:
2103:
2088:
2056:
2039:
2007:
1881:
1840:
1830:
1256:
1058:
924:
880:
875:
858:
808:, is a variant of this concept. Each year of this calendar can be up to 371 days long.
778:
653:
602:
525:
453:
394:
1630:
3035:
2580:
2533:
2523:
2478:
2473:
2318:
2293:
2266:
2207:
2190:
2061:
2044:
1925:
1896:
1765:
1325:
1195:
960:
912:
755:
703:
Its epoch, i.e. start of the year count, is religious. The same applies to month and
521:
484:
390:
386:
341:
1770:
1036:
There have been many specific calendar proposals to replace the Gregorian calendar:
2917:
2892:
2767:
2695:
2185:
1078:
931:
849:
834:
793:
645:
503:
488:
675:. Each year starts on a different day of the week and calendars expire every year.
1397:
1372:
551:, while 1700, 1800, 1900, 2100, 2200, 2300, 2500, 2600, 2700, 2900, and 3000 are
2897:
2823:
2792:
2787:
2705:
2543:
2195:
1166:
1144:
1083:
888:
805:
797:
711:
552:
319:
158:
37:
678:
It is difficult to determine the weekday of any given day of the year or month.
2912:
2907:
2842:
2832:
2827:
2652:
2202:
2017:
1171:
1093:
1009:
736:
It is hard or even impossible to solve all these issues in just one calendar.
436:
382:
1776:
1339:
2990:
2954:
2922:
2818:
2797:
2777:
1901:
992:
interval of the traditional fixed arithmetic Hebrew calendar, respectively.
771:
721:
648:, the newly formed United Nations continued efforts of its predecessor, the
548:
315:
286:
is possible without disruption. Examples of this include the changes to the
17:
1039:
The following count one or more days outside the standard seven-day week:
555:
despite being divisible by 4. This rule makes the mean year 365.2425 days
476:
changed it from an observational calendar into a calculated calendar. The
2985:
2961:
2782:
2538:
1816:
863:
682:
641:
627:
345:
330:
142:
838:
786:
704:
630:, with some differences from traditional conceptions in many cultures.
183: in this section. Unsourced material may be challenged and removed.
1024:
uses 12 or 13 lunar months named after 13 contributors to research on
988:
interval, intended to replace the 19-year leap cycle and the constant
974:
Some propose to improve leap rules of existing calendars, such as the
640:
was one such official reform, but was abolished twelve years later by
1089:
There have also been proposals to revise the way years are numbered:
307:
Most calendars have several rules which could be altered by reform:
1515:
952:
Lunisolar calendars usually have 12 or 13 months of 29 or 30 days.
452:
been at least four similar reforms of the lunisolar version of the
255:
The prime objective of a calendar is to unambiguously identify any
2772:
984:
967:
852:) in 1793. It consisted of twelve months, each divided into three
594:
576:
502:
264:
2902:
1005:
729:
725:
351:
If a week is retained, the start, length, and names of its days.
268:
260:
1789:
360:
Special days and periods (such as leap day or intercalary day).
256:
152:
31:
667:
Reformers cite several problems with the Gregorian calendar:
357:
If months are retained, number, lengths, and names of months.
1785:
1709:
1681:
Marking Time: The Epic Quest to Invent the Perfect Calendar
1600:
Marking Time: The Epic Quest to Invent the Perfect Calendar
1485:
Marking Time: The Epic Quest to Invent the Perfect Calendar
1426:
Marking Time: The Epic Quest to Invent the Perfect Calendar
1246:, corrected printing (Oxford University Press, 2013), 692.
919:
is a more modern descendant of this calendar: invented by
856:
of ten days, with five or six intercalary days called
354:
Start of the day (midnight, sunrise, noon, or sunset).
447:
There have been 50 to 100 reforms of the traditional
938:
to the 364-day common year for 71 out of 400 years.
2942:
2806:
2760:
2749:
2719:
2676:
2611:
2414:
2360:
2327:
1910:
1849:
1823:
1751:(very brief mention in New York Times op-ed page) (
934:, which avoids off-calendar days by adding a 7-day
62:. Unsourced material may be challenged and removed.
1678:
1597:
1482:
1423:
1194:
874:The lengths of the months inherited from the old
1242:Bonnie Blackburn and Leofranc Holford-Strevens,
833:A decimal calendar is a calendar which includes
416:A typical solution to force synchronization is
1570:Pappas, Stephanie Pappas (December 29, 2011).
656:but postponed the issue after a veto from the
557:(365 d, 5 h, 49 min, 12 s)
491:and others, developing the precisely computed
1801:
1773:in which each year has either 364 or 371 days
930:Around 1930, one James Colligan invented the
614:or New calendar, but was rejected by others.
8:
1276:World Council of Churches (March 10, 1997).
700:that are equal would make accounting easier.
528:had ceased to reflect the year accurately.
3006:
2757:
1918:
1808:
1794:
1786:
1197:Mapping Time: The Calendar and its History
781:, favored by the UN in the 1950s, and the
1223:"The Christian Calendar | Calendars"
243:Learn how and when to remove this message
122:Learn how and when to remove this message
27:Significant revision of a calendar system
1307:
1305:
1303:
1265:. Vatican Observatory. pp. 265–279.
792:Some calendar reform ideas, such as the
1185:
1069:The following are leap week calendars:
468:zodiacal sign. The same applies to the
443:Reform of lunar and lunisolar calendars
1572:"Is It Time to Overhaul the Calendar?"
1367:
1365:
1314:Journal for Eighteenth-Century Studies
710:Each month has no connection with the
1398:"The Meyer–Palmen Solilunar Calendar"
472:. The first millennium reform of the
460:year. There have been reforms of the
325:Numbering of years, selection of the
7:
1125:Determination of the day of the week
879:month is longer than the other two.
693:) to remember the lengths of months.
181:adding citations to reliable sources
60:adding citations to reliable sources
1653:Masonic Lodge of Education (2019),
1201:. Oxford University Press. Ch. 18.
1163:("On reckoning the years"), c. 1235
366:Alignment with astronomical cycles.
1373:"The Hermetic Lunar Week Calendar"
1278:"Towards a Common Date for Easter"
1151:Precursors of the Gregorian reform
971:divided into it in this calendar.
25:
566:), ten days were dropped so that
369:Alignment with biological cycles.
141:is any significant revision of a
3016:
3015:
3005:
1326:10.1111/j.1754-0208.2011.00408.x
1244:The Oxford Companion to the Year
1104:Reform of the Islamic calendar:
862:. The calendar was abolished by
483:Another reform was performed in
157:
36:
2868:English and British regnal year
732:, with nothing in between them.
658:government of the United States
581:Julian to Gregorian Date Change
336:Start of the year (such as the
168:needs additional citations for
47:needs additional citations for
1135:Hanke–Henry Permanent Calendar
1074:Hanke–Henry Permanent Calendar
885:Hanke–Henry Permanent Calendar
802:Hanke–Henry Permanent Calendar
1:
1766:Home Page for Calendar Reform
1542:, Doubleday, pp. 48–58,
720:The calendar does not have a
405:, when it was altered to the
363:Alignment with social cycles.
1685:. New York: Wiley. pp.
1659:, Masonic Lodge of Education
1514:World Calendar Association,
1044:International Fixed Calendar
1022:Hermetic Lunar Week Calendar
957:Hermetic Lunar Week Calendar
917:International Fixed Calendar
783:International Fixed Calendar
652:, to establish the proposed
499:Julian and Gregorian reforms
1604:. New York: Wiley. p.
1489:. New York: Wiley. p.
1430:. New York: Wiley. p.
848:was introduced (along with
3063:
1725:Segura, Wenceslao (2012).
945:
923:and financially backed by
846:French Republican Calendar
826:
747:
687:Thirty days hath September
638:French Republican Calendar
545:leap year rule was altered
372:Literal notation of dates.
3001:
1921:
1728:La reforma del calendario
1175:("Greater Work"), c. 1267
980:Rectified Hebrew calendar
740:lunar-centric proposals.
662:World Council of Churches
599:Eastern Orthodox Churches
513:An Election Entertainment
1780:"Reform of the Calendar"
1632:The Symmetry454 Calendar
1193:Richards, E. G. (1998).
707:names in many languages.
524:took power in Rome, the
1936:Assamese (Bhāshkarābda)
1635:, University of Toronto
1540:The Tragedy of the Moon
1340:"The Georgian Calendar"
1120:Abolition of time zones
612:Revised Julian calendar
2967:Dungeons & Dragons
2373:Ethiopian and Eritrean
1782:Historical information
1677:Steel, Duncan (2000).
1596:Steel, Duncan (2000).
1538:Asimov, Isaac (1973),
1520:, theworldcalendar.org
1517:The World Calendar.org
1481:Steel, Duncan (2000).
1422:Steel, Duncan (2000).
1157:Johannes de Sacrobosco
582:
517:
340:, January 1, March 1,
2979:The Lord of the Rings
2686:Hanke–Henry Permanent
1778:Catholic Encyclopedia
1064:World Season Calendar
817:World Season Calendar
580:
506:
1760:. February 27, 2011.
1749:Kluznickian Calendar
1008:or March from Roman
866:on January 1, 1806.
322:and how they differ.
177:improve this article
56:improve this article
2691:International Fixed
2629:Proleptic Gregorian
2250:Slavic Native Faith
1771:Leap week calendars
1576:Scientific American
1548:1973trmo.book.....A
1288:on October 12, 2012
1054:Positivist calendar
1049:Invariable Calendar
1026:psychoactive plants
942:Lunisolar calendars
911:(1849), created by
909:Positivist calendar
760:leap week calendars
744:Perennial calendars
399:lunisolar calendars
329:, and the issue of
3042:Proposed calendars
2361:Christian variants
1032:Specific proposals
948:Lunisolar calendar
921:Moses B. Cotsworth
895:13-month calendars
870:12-month calendars
823:10-month calendars
750:Perennial calendar
624:Gregorian calendar
591:Milutin Milanković
583:
518:
407:Gregorian calendar
377:Historical reforms
302:proleptic calendar
274:Once specified, a
139:calendrical reform
3029:
3028:
3011:List of calendars
2938:
2937:
2637:historiographical
2504:French Republican
2410:
2409:
2168:Manipuri (Meitei)
1754:"Except February"
1737:978-84-616-1729-6
1282:www.oikoumene.org
1140:List of calendars
1099:Holocene calendar
800:calendar and the
724:: the year after
698:Business quarters
650:League of Nations
541:Pope Gregory XIII
470:Buddhist calendar
338:December solstice
253:
252:
245:
227:
192:"Calendar reform"
132:
131:
124:
106:
71:"Calendar reform"
16:(Redirected from
3054:
3019:
3018:
3009:
3008:
2873:Human (Holocene)
2858:Chinese Imperial
2758:
2678:Reform proposals
2633:Proleptic Julian
2395:Eastern Orthodox
2025:Germanic heathen
2003:Earthly Branches
1919:
1810:
1803:
1796:
1787:
1761:
1713:
1707:
1701:
1700:
1684:
1674:
1668:
1667:
1666:
1664:
1656:Masonic Calendar
1650:
1644:
1643:
1642:
1640:
1626:
1620:
1619:
1603:
1593:
1587:
1586:
1584:
1582:
1567:
1561:
1560:
1535:
1529:
1528:
1527:
1525:
1511:
1505:
1504:
1488:
1478:
1472:
1471:
1469:
1467:
1452:
1446:
1445:
1429:
1419:
1413:
1412:
1410:
1408:
1394:
1388:
1387:
1385:
1383:
1369:
1360:
1357:
1351:
1350:
1348:
1346:
1336:
1330:
1329:
1309:
1298:
1297:
1295:
1293:
1284:. Archived from
1273:
1267:
1266:
1253:
1247:
1240:
1234:
1233:
1231:
1229:
1219:
1213:
1212:
1200:
1190:
1130:Decimal calendar
829:Decimal calendar
764:intercalary days
691:knuckle counting
608:
573:
569:
565:
558:
478:Islamic calendar
449:Chinese calendar
314:Which years are
292:Islamic calendar
288:Chinese calendar
248:
241:
237:
234:
228:
226:
185:
161:
153:
127:
120:
116:
113:
107:
105:
64:
40:
32:
21:
3062:
3061:
3057:
3056:
3055:
3053:
3052:
3051:
3032:
3031:
3030:
3025:
2997:
2934:
2888:Nirayana system
2814:Ab urbe condita
2802:
2754:
2752:
2745:
2724:
2722:
2715:
2672:
2623:anthropological
2607:
2406:
2390:Liturgical year
2356:
2323:
1915:
1913:
1906:
1845:
1819:
1814:
1752:
1745:
1722:
1720:Further reading
1717:
1716:
1708:
1704:
1697:
1676:
1675:
1671:
1662:
1660:
1652:
1651:
1647:
1638:
1636:
1629:Bromberg, Irv,
1628:
1627:
1623:
1616:
1595:
1594:
1590:
1580:
1578:
1569:
1568:
1564:
1558:
1537:
1536:
1532:
1523:
1521:
1513:
1512:
1508:
1501:
1480:
1479:
1475:
1465:
1463:
1462:. June 26, 1910
1454:
1453:
1449:
1442:
1421:
1420:
1416:
1406:
1404:
1402:www.hermetic.ch
1396:
1395:
1391:
1381:
1379:
1377:www.hermetic.ch
1371:
1370:
1363:
1358:
1354:
1344:
1342:
1338:
1337:
1333:
1311:
1310:
1301:
1291:
1289:
1275:
1274:
1270:
1257:Gingerich, Owen
1255:
1254:
1250:
1241:
1237:
1227:
1225:
1221:
1220:
1216:
1209:
1192:
1191:
1187:
1182:
1161:De Anni Ratione
1116:
1034:
1028:and chemicals.
1018:
998:
976:Hebrew calendar
950:
944:
902:Rev. Hugh Jones
897:
872:
831:
825:
752:
746:
620:
606:
571:
567:
563:
556:
508:William Hogarth
501:
493:Jalali calendar
474:Hebrew calendar
445:
403:Julian calendar
379:
284:calendar system
276:calendar design
249:
238:
232:
229:
186:
184:
174:
162:
151:
135:Calendar reform
128:
117:
111:
108:
65:
63:
53:
41:
28:
23:
22:
15:
12:
11:
5:
3060:
3058:
3050:
3049:
3044:
3034:
3033:
3027:
3026:
3024:
3023:
3013:
3002:
2999:
2998:
2996:
2995:
2983:
2971:
2959:
2946:
2944:
2940:
2939:
2936:
2935:
2933:
2932:
2927:
2926:
2925:
2920:
2915:
2910:
2900:
2895:
2890:
2885:
2880:
2875:
2870:
2865:
2863:Chinese Minguo
2860:
2855:
2853:Before Present
2850:
2845:
2840:
2835:
2830:
2821:
2816:
2810:
2808:
2804:
2803:
2801:
2800:
2795:
2790:
2785:
2780:
2775:
2770:
2764:
2762:
2755:
2750:
2747:
2746:
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2738:
2733:
2727:
2725:
2720:
2717:
2716:
2714:
2713:
2708:
2703:
2698:
2693:
2688:
2682:
2680:
2674:
2673:
2671:
2670:
2665:
2660:
2659:
2658:
2650:
2649:
2648:
2640:
2639:
2638:
2626:
2625:
2624:
2615:
2613:
2609:
2608:
2606:
2605:
2600:
2595:
2590:
2585:
2578:
2573:
2568:
2563:
2558:
2553:
2548:
2547:
2546:
2541:
2531:
2526:
2521:
2516:
2511:
2506:
2501:
2496:
2491:
2486:
2481:
2476:
2471:
2466:
2461:
2456:
2451:
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2445:
2444:
2439:
2429:
2424:
2418:
2416:
2412:
2411:
2408:
2407:
2405:
2404:
2399:
2398:
2397:
2387:
2386:
2385:
2375:
2370:
2364:
2362:
2358:
2357:
2355:
2354:
2353:
2352:
2350:Calendar round
2347:
2337:
2331:
2329:
2325:
2324:
2322:
2321:
2316:
2311:
2306:
2301:
2296:
2291:
2286:
2281:
2280:
2279:
2274:
2264:
2259:
2258:
2257:
2252:
2242:
2237:
2232:
2227:
2222:
2221:
2220:
2210:
2205:
2200:
2199:
2198:
2193:
2188:
2180:
2175:
2170:
2165:
2160:
2155:
2150:
2145:
2140:
2139:
2138:
2128:
2123:
2118:
2113:
2112:
2111:
2106:
2096:
2095:
2094:
2086:
2085:
2084:
2079:
2078:
2077:
2064:
2059:
2054:
2053:
2052:
2047:
2037:
2032:
2027:
2022:
2021:
2020:
2015:
2010:
2008:Heavenly Stems
2005:
1995:
1990:
1985:
1980:
1979:
1978:
1968:
1967:
1966:
1961:
1953:
1952:
1951:
1943:
1938:
1933:
1928:
1922:
1916:
1911:
1908:
1907:
1905:
1904:
1899:
1894:
1889:
1884:
1879:
1874:
1869:
1864:
1859:
1853:
1851:
1847:
1846:
1844:
1843:
1838:
1833:
1827:
1825:
1821:
1820:
1815:
1813:
1812:
1805:
1798:
1790:
1784:
1783:
1774:
1768:
1763:
1758:New York Times
1744:
1743:External links
1741:
1740:
1739:
1721:
1718:
1715:
1714:
1702:
1695:
1669:
1645:
1621:
1614:
1588:
1562:
1556:
1530:
1506:
1499:
1473:
1460:New York Times
1447:
1440:
1414:
1389:
1361:
1352:
1331:
1299:
1268:
1248:
1235:
1214:
1208:978-0192862051
1207:
1184:
1183:
1181:
1178:
1177:
1176:
1164:
1153:
1152:
1148:
1147:
1142:
1137:
1132:
1127:
1122:
1115:
1112:
1111:
1110:
1102:
1101:
1096:
1087:
1086:
1081:
1076:
1067:
1066:
1061:
1059:World Calendar
1056:
1051:
1046:
1033:
1030:
1017:
1014:
997:
994:
961:vernal equinox
943:
940:
925:George Eastman
896:
893:
881:World Calendar
876:Roman calendar
871:
868:
859:sansculottides
839:decimal system
827:Main article:
824:
821:
779:World Calendar
745:
742:
734:
733:
718:
715:
708:
701:
694:
679:
676:
654:World Calendar
619:
616:
603:Constantinople
593:proposed to a
526:Roman calendar
500:
497:
454:Hindu calendar
444:
441:
432:
431:
428:
425:
378:
375:
374:
373:
370:
367:
364:
361:
358:
355:
352:
349:
334:
323:
312:
251:
250:
233:September 2019
165:
163:
156:
150:
147:
130:
129:
44:
42:
35:
26:
24:
14:
13:
10:
9:
6:
4:
3:
2:
3059:
3048:
3045:
3043:
3040:
3039:
3037:
3022:
3014:
3012:
3004:
3003:
3000:
2993:
2992:
2987:
2984:
2981:
2980:
2975:
2972:
2969:
2968:
2963:
2960:
2957:
2956:
2951:
2948:
2947:
2945:
2941:
2931:
2928:
2924:
2921:
2919:
2916:
2914:
2911:
2909:
2906:
2905:
2904:
2901:
2899:
2896:
2894:
2891:
2889:
2886:
2884:
2881:
2879:
2876:
2874:
2871:
2869:
2866:
2864:
2861:
2859:
2856:
2854:
2851:
2849:
2846:
2844:
2841:
2839:
2838:Anno Martyrum
2836:
2834:
2831:
2829:
2825:
2822:
2820:
2817:
2815:
2812:
2811:
2809:
2805:
2799:
2796:
2794:
2791:
2789:
2786:
2784:
2781:
2779:
2776:
2774:
2771:
2769:
2766:
2765:
2763:
2759:
2756:
2753:and numbering
2748:
2742:
2739:
2737:
2734:
2732:
2729:
2728:
2726:
2718:
2712:
2709:
2707:
2704:
2702:
2699:
2697:
2694:
2692:
2689:
2687:
2684:
2683:
2681:
2679:
2675:
2669:
2668:'Pataphysical
2666:
2664:
2661:
2656:
2655:
2654:
2651:
2646:
2645:
2644:
2641:
2636:
2635:
2634:
2630:
2627:
2622:
2621:
2620:
2617:
2616:
2614:
2610:
2604:
2601:
2599:
2596:
2594:
2591:
2589:
2586:
2584:
2583:
2579:
2577:
2574:
2572:
2569:
2567:
2564:
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2559:
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2542:
2540:
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2535:
2532:
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2522:
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2517:
2515:
2512:
2510:
2507:
2505:
2502:
2500:
2497:
2495:
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2487:
2485:
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2480:
2477:
2475:
2472:
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2467:
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2462:
2460:
2457:
2455:
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2450:
2447:
2443:
2440:
2438:
2437:Tōnalpōhualli
2435:
2434:
2433:
2430:
2428:
2425:
2423:
2420:
2419:
2417:
2413:
2403:
2400:
2396:
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2392:
2391:
2388:
2384:
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2379:
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2363:
2359:
2351:
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2312:
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2295:
2292:
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2287:
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2275:
2273:
2270:
2269:
2268:
2265:
2263:
2260:
2256:
2253:
2251:
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2246:
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2241:
2238:
2236:
2233:
2231:
2228:
2226:
2223:
2219:
2216:
2215:
2214:
2211:
2209:
2206:
2204:
2201:
2197:
2194:
2192:
2191:Vikram Samvat
2189:
2187:
2184:
2183:
2181:
2179:
2176:
2174:
2171:
2169:
2166:
2164:
2161:
2159:
2156:
2154:
2151:
2149:
2146:
2144:
2141:
2137:
2134:
2133:
2132:
2129:
2127:
2124:
2122:
2119:
2117:
2114:
2110:
2107:
2105:
2102:
2101:
2100:
2097:
2092:
2091:
2090:
2087:
2083:
2080:
2075:
2074:
2073:
2070:
2069:
2068:
2065:
2063:
2060:
2058:
2055:
2051:
2048:
2046:
2045:Vikram Samvat
2043:
2042:
2041:
2038:
2036:
2033:
2031:
2028:
2026:
2023:
2019:
2016:
2014:
2011:
2009:
2006:
2004:
2001:
2000:
1999:
1996:
1994:
1991:
1989:
1986:
1984:
1981:
1977:
1974:
1973:
1972:
1969:
1965:
1962:
1960:
1957:
1956:
1954:
1949:
1948:
1947:
1944:
1942:
1939:
1937:
1934:
1932:
1929:
1927:
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1909:
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1900:
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1893:
1890:
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1865:
1863:
1860:
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1834:
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1829:
1828:
1826:
1822:
1818:
1811:
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1799:
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1791:
1788:
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1734:
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1723:
1719:
1711:
1706:
1703:
1698:
1696:0-471-29827-1
1692:
1688:
1683:
1682:
1673:
1670:
1658:
1657:
1649:
1646:
1634:
1633:
1625:
1622:
1617:
1615:0-471-29827-1
1611:
1607:
1602:
1601:
1592:
1589:
1577:
1573:
1566:
1563:
1559:
1557:0-440-18999-3
1553:
1549:
1545:
1541:
1534:
1531:
1519:
1518:
1510:
1507:
1502:
1500:0-471-29827-1
1496:
1492:
1487:
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1474:
1461:
1457:
1451:
1448:
1443:
1441:0-471-29827-1
1437:
1433:
1428:
1427:
1418:
1415:
1403:
1399:
1393:
1390:
1378:
1374:
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1341:
1335:
1332:
1327:
1323:
1319:
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1279:
1272:
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1258:
1252:
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1224:
1218:
1215:
1210:
1204:
1199:
1198:
1189:
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1179:
1174:
1173:
1168:
1165:
1162:
1158:
1155:
1154:
1150:
1149:
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1138:
1136:
1133:
1131:
1128:
1126:
1123:
1121:
1118:
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1107:
1106:
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1100:
1097:
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1077:
1075:
1072:
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1065:
1062:
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1041:
1040:
1037:
1031:
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1023:
1015:
1013:
1011:
1007:
1002:
995:
993:
991:
987:
986:
981:
977:
972:
969:
964:
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958:
953:
949:
941:
939:
937:
933:
928:
926:
922:
918:
914:
913:Auguste Comte
910:
905:
903:
894:
892:
890:
886:
882:
877:
869:
867:
865:
861:
860:
855:
851:
847:
842:
840:
837:based on the
836:
835:units of time
830:
822:
820:
818:
813:
809:
807:
803:
799:
795:
790:
788:
784:
780:
775:
774:of ISO 8601.
773:
767:
765:
761:
757:
751:
743:
741:
737:
731:
727:
723:
719:
716:
713:
709:
706:
702:
699:
695:
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688:
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677:
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613:
604:
600:
596:
592:
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579:
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533:Julian reform
529:
527:
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522:Julius Caesar
515:
514:
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486:
485:Seljuk Persia
481:
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422:
421:
419:
418:intercalation
414:
410:
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396:
392:
391:synodic month
389:) and/or the
388:
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350:
347:
343:
342:March equinox
339:
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295:
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282:of the local
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194: –
193:
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188:Find sources:
182:
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172:
171:
166:This section
164:
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126:
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73: –
72:
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67:Find sources:
61:
57:
51:
50:
45:This article
43:
39:
34:
33:
30:
19:
2989:
2977:
2974:Middle-earth
2965:
2953:
2723:applications
2721:Displays and
2677:
2631: /
2612:By specialty
2581:
2442:Xiuhpōhualli
2340:Mesoamerican
2186:Nepal Sambat
1857:Astronomical
1777:
1757:
1727:
1705:
1680:
1672:
1661:, retrieved
1655:
1648:
1637:, retrieved
1631:
1624:
1599:
1591:
1579:. Retrieved
1575:
1565:
1539:
1533:
1522:, retrieved
1516:
1509:
1484:
1476:
1464:. Retrieved
1459:
1450:
1425:
1417:
1405:. Retrieved
1401:
1392:
1380:. Retrieved
1376:
1355:
1343:. Retrieved
1334:
1317:
1313:
1290:. Retrieved
1286:the original
1281:
1271:
1261:
1251:
1243:
1238:
1226:. Retrieved
1217:
1196:
1188:
1170:
1160:
1103:
1088:
1079:Pax Calendar
1068:
1038:
1035:
1019:
1003:
999:
989:
983:
973:
965:
954:
951:
932:Pax Calendar
929:
906:
898:
873:
857:
853:
850:decimal time
843:
832:
814:
810:
806:fiscal years
794:Pax Calendar
791:
776:
768:
753:
738:
735:
712:lunar phases
666:
646:World War II
632:
621:
588:
584:
561:
553:common years
538:
530:
519:
511:
489:Omar Khayyam
482:
465:
461:
457:
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415:
411:
380:
320:common years
306:
301:
299:
296:
283:
279:
275:
273:
254:
239:
230:
220:
213:
206:
199:
187:
175:Please help
170:verification
167:
138:
134:
133:
118:
109:
99:
92:
85:
78:
66:
54:Please help
49:verification
46:
29:
18:New Calendar
2824:Anno Domini
2793:Regnal year
2788:Regnal name
2761:Terminology
2751:Year naming
2706:Symmetry454
2556:Pentecontad
2479:Culāsakaraj
2464:Cappadocian
2196:Yele Sambat
2082:Zoroastrian
1976:Bangladeshi
1914:limited use
1892:Solar Hijri
1887:Lunar Hijri
1850:In wide use
1345:February 2,
1292:October 13,
1167:Roger Bacon
1145:Metric time
1109:separately.
1084:Symmetry454
889:Symmetry454
798:Symmetry454
3036:Categories
2930:Vietnamese
2843:Anno Mundi
2833:Anno Lucis
2828:Common Era
2731:Electronic
2701:Positivist
2663:Discordian
2653:Dreamspell
2588:Sexagenary
2529:Macedonian
2499:Florentine
2449:Babylonian
2415:Historical
2345:Long Count
2299:Vietnamese
2255:Macedonian
2218:Nanakshahi
2148:Lithuanian
2018:Solar term
1663:October 4,
1639:October 4,
1581:October 4,
1524:October 4,
1466:October 4,
1180:References
1172:Opus Majus
1094:Anno Lucis
946:See also:
748:See also:
671:It is not
572:October 15
549:leap years
437:Stonehenge
316:leap years
203:newspapers
149:Principles
82:newspapers
2991:Star Trek
2955:Discworld
2950:Discworld
2943:Fictional
2819:Anka year
2798:Year zero
2778:Leap year
2736:Perpetual
2459:Byzantine
2178:Mongolian
2158:Malayalam
1902:Unix time
1877:Gregorian
1872:Ethiopian
1836:Lunisolar
1817:Calendars
936:leap week
772:week date
722:year zero
683:mnemonics
673:perennial
618:Proposals
589:In 1923,
574:in 1582.
568:October 5
331:year zero
112:June 2021
3021:Category
2986:Stardate
2962:Greyhawk
2893:Seleucid
2878:Japanese
2848:Assyrian
2783:New Year
2619:Holocene
2571:Rapa Nui
2544:Tzolkʼin
2509:Germanic
2489:Egyptian
2225:Romanian
2203:Nisg̱a'a
2163:Mandaean
2153:Maithili
2126:Javanese
2121:Japanese
2076:medieval
2030:Georgian
1941:Assyrian
1931:Armenian
1862:Buddhist
1407:June 21,
1382:June 21,
1320:: 1–16.
1114:See also
1016:Examples
864:Napoleon
787:Sabbaths
685:(e.g., "
644:. After
642:Napoleon
628:ISO 8601
597:of some
564:March 21
466:sidereal
458:sidereal
387:sidereal
346:Lady Day
143:calendar
2918:Dvapara
2898:Spanish
2807:Systems
2657:New Age
2647:Martian
2603:Turkmen
2598:Swedish
2484:Coligny
2422:Arabian
2383:Revised
2289:Tripuri
2284:Tibetan
2240:Sesotho
2213:Punjabi
2173:Melanau
2143:Kurdish
2109:Tabular
2099:Islamic
2067:Iranian
1998:Chinese
1993:Burmese
1971:Bengali
1959:Pawukon
1912:In more
1867:Chinese
1824:Systems
1687:149–151
1544:Bibcode
1228:May 22,
854:décades
815:In the
705:weekday
635:decimal
570:became
217:scholar
96:scholar
3047:Reform
2883:Korean
2643:Darian
2593:Soviet
2566:Qumran
2551:Muisca
2469:Celtic
2454:Bulgar
2402:Saints
2378:Julian
2368:Coptic
2314:Yoruba
2245:Slavic
2235:Somali
2182:Nepal
2131:Korean
2093:Gaelic
2072:Jalali
2035:Hebrew
2013:Minguo
1988:Borana
1983:Berber
1946:Baháʼí
1735:
1693:
1612:
1554:
1497:
1438:
1205:
996:Naming
978:. The
543:, the
539:Under
280:reform
267:, and
265:months
219:
212:
205:
198:
190:
98:
91:
84:
77:
69:
2913:Treta
2908:Satya
2903:Yugas
2773:Epoch
2711:World
2576:Roman
2561:Pisan
2539:Haabʼ
2519:Hindu
2514:Greek
2494:Enoch
2432:Aztec
2427:Attic
2335:Runic
2328:Types
2309:Xhosa
2304:Wicca
2277:solar
2272:lunar
2262:Tamil
2230:Shona
2136:Juche
2104:Fasli
2089:Irish
2057:Hmong
2040:Hindu
1955:Bali
1950:Badí‘
1882:Hindu
1841:Solar
1831:Lunar
990:molad
985:molad
968:Meton
689:" or
595:synod
520:When
462:solar
395:lunar
383:solar
327:epoch
269:years
261:weeks
224:JSTOR
210:books
103:JSTOR
89:books
2923:Kali
2741:Wall
2582:Rumi
2534:Maya
2524:Inca
2474:Cham
2319:Zulu
2294:Tulu
2267:Thai
2208:Odia
2116:Jain
2062:Igbo
2050:Saka
1964:Saka
1926:Akan
1733:ISBN
1691:ISBN
1665:2019
1641:2019
1610:ISBN
1583:2019
1552:ISBN
1526:2019
1495:ISBN
1468:2019
1436:ISBN
1409:2021
1384:2021
1347:2015
1294:2007
1230:2019
1203:ISBN
1010:Mars
1006:Thor
955:The
907:The
883:and
844:The
777:The
762:and
756:date
730:1 AD
728:was
726:1 BC
622:The
531:The
318:and
196:news
75:news
2768:Era
2696:Pax
1897:ISO
1606:288
1491:308
1432:309
1322:doi
601:at
510:'s
487:by
397:or
393:in
385:or
257:day
179:by
137:or
58:by
3038::
1756:.
1731:.
1689:.
1608:.
1574:.
1550:,
1493:.
1458:.
1434:.
1400:.
1375:.
1364:^
1318:35
1316:.
1302:^
1280:.
1169:,
1159:,
963:.
927:.
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348:).
344:,
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1618:.
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1546::
1503:.
1470:.
1444:.
1411:.
1386:.
1349:.
1328:.
1324::
1296:.
1232:.
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714:.
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246:)
240:(
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231:(
221:·
214:·
207:·
200:·
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114:)
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100:·
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86:·
79:·
52:.
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