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Leap Year

Leap year

A leap year (or intercalary year) is a year containing an extra day or month in order to keep the calendar year in sync with an astronomical or seasonal year. Seasons and astronomical events do not repeat at an exact number of days, so a calendar which had the same number of days in each year would over time drift with respect to the event it was supposed to track. By occasionally inserting (or intercalating) an additional day or month into the year, the drift can be corrected. Leap years (which keep the calendar in sync with the year) should not be confused with leap seconds (which keep clock time in sync with the day).

Gregorian calendar

The Gregorian calendar, the current standard calendar in most of the world, adds a 29th day to February in all years evenly divisible by 4, except for century years (those ending in -00), which receive the extra day only if they are evenly divisible by 400. Thus 1996 was a leap year whereas 1999 was not, and 1600, 2000 and 2400 are leap years but 1700, 1800, 1900 and 2100 are not. The reasoning behind this rule is as follows:
- The Gregorian calendar is designed to keep the vernal equinox on or close to March 21, so that the date of Easter (celebrated on the Sunday after the 14th day of the Moon that falls on or after 21 March) remains correct with respect to the vernal equinox.
- The vernal equinox year is currently about 365.242375 days long.
- The Gregorian leap year rule gives an average year length of 365.2425 days. This difference of a little over 0.0001 days means that in around 8,000 years, the calendar will be about one day behind where it should be. But in 8,000 years' time the length of the vernal equinox year will have changed by an amount we can't accurately predict (see below). So the Gregorian leap year rule does a good enough job. Image:Gregoriancalendarleap.png

Which day is the leap day?

The Gregorian calendar is a modification of the Julian calendar first used by the Romans. The Roman calendar originated as a lunar calendar (though from the 5th century BC it no longer followed the real moon) and named its days after three of the phases of the moon: the new moon (calends, hence "calendar"), the first quarter (nones) and the full moon (ides). Days were counted down (inclusively) to the next named day, so 24 February was ante diem sextum calendas martii ("the sixth day before the calends of March"). Since 45 BC, February in a leap year had two days called "the sixth day before the calends of March". The extra day was originally the second of these, but since the third century it was the first. Hence the term bissextile day for 24 February in a bissextile year. Where this custom is followed, anniversaries after the inserted day are moved in leap years. For example, the former feast day of Saint Matthias, 24 February in ordinary years, would be 25 February in leap years. This historical nicety is, however, in the process of being discarded: The European Union declared that, starting in 2000, 29 February rather than 24 February would be leap day, and the Roman Catholic Church also now uses 29 February as leap day. The only tangible difference is felt in countries that celebrate feast days.

Julian calendar

The Julian calendar adds an extra day to February in years divisible by 4. This rule gives an average year length of 365.25 days. The excess of about 0.0076 days with respect to the vernal equinox year means that the vernal equinox moves a day earlier in the calendar every 130 years or so.

Revised Julian Calendar

The Revised Julian calendar adds an extra day to February in years divisible by 4, except for years divisible by 100 that do not leave a remainder of 200 or 600 when divided by 900. This rule agrees with the rule for the Gregorian calendar until 2799. The first year that dates in the Revised Julian calendar will not agree with the those in the Gregorian calendar will be 2800, because it will be a leap year in the Gregorian calendar but not in the Revised Julian calendar. This rule gives an average year length of 365.242222… days. This is a very good approximation to the mean tropical year, but because the vernal equinox tropical year is slightly longer, the Revised Julian calendar does not do as good a job as the Gregorian calendar of keeping the vernal equinox on or close to 21 March.

Chinese calendar

The Chinese calendar is lunisolar, so a leap year has an extra month, often called an embolismic month after the Greek word for it. In the Chinese calendar the leap month is added according to a complicated rule, which ensures that month 11 is always the month that contains the northern winter solstice. The intercalary month takes the same number as the preceding month; for example, if it follows the second month then it is simply called "leap second month".

Hebrew calendar

The Hebrew calendar is also lunisolar with an embolistic month. In the Hebrew calendar the extra month is called Adar Alef (first Adar) and is added before Adar, which then becomes Adar Sheni (second Adar). According to the Metonic cycle, this is done seven times every nineteen years, specifically, in years, 3, 6, 8, 11, 14, 17, and 19. In addition, the Hebrew calendar has postponement rules that postpone the start of the year by one or two days. The year before the postponement gets one or two extra days, and the year whose start is postponed loses one or two days. These postponement rules reduce the number of different combinations of year length and starting day of the week from 28 to 14, and regulate the location of certain religious holidays in relation to the Sabbath.

Hindu Calendar

In the Hindu calendar, which is a lunisolar calendar, the embolismic month is called adhika maas (extra month). It is the month in which the sun is in the same sign of the stellar zodiac on two consecutive dark moons.

Iranian calendar

The Iranian calendar also has a single intercalated day once in every four years, but every 33 years or so the leap years will be five years apart instead of four years apart. The system used is more accurate and more complicated, and is based on the time of the March equinox as observed from Teheran. The 33-year period is not completely regular; every so often the 33-year cycle will be broken by a cycle of 29 or 37 years.

Long term leap year rules

The accumulated difference between the Gregorian calendar and the vernal equinoctial year amounts to 1 day in about 8,000 years. This suggests that the calendar needs to be improved by another refinement to the leap year rule: perhaps by avoiding leap years in years divisible by 8,000. (The most common such proposal is to avoid leap years in years divisible by 4,000 [http://www.google.com/search?q=%22gregorian+calendar%22+error+%22leap+year%22+4000]. This is based on the difference between the Gregorian calendar and the mean tropical year. Others claim, erroneously, that the Gregorian calendar itself already contains a refinement of this kind [http://www.straightdope.com/mailbag/mleapyr.html].) However, there is little point in planning a calendar so far ahead because over a timescale of tens of thousands of years the number of days in a year will change for a number of reasons, most notably: #Precession of the equinoxes moves the position of the vernal equinox with respect to perihelion and so changes the length of the vernal equinoctial year. #Tidal acceleration from the sun and moon slows the rotation of the earth, making the day longer. In particular, the second component of change depends on such things as post-glacial rebound and sea level rise due to climate change. We can't predict these changes accurately enough to be able to make a calendar that will be accurate to a day in tens of thousands of years.

Marriage proposal

There is a tradition, said to go back to Saint Patrick and Saint Bridget in 5th century Ireland, whereby women may only make marriage proposals in leap years.

Saint Patrick and the leap year

:Saint Patrick, having driven the frogs out of the bogs was walking along the shores of Lough Neagh, when he was accosted by Saint Bridget in tears, and was told that a mutiny had broken out in the nunnery over which she presided, the ladies claiming the right of popping the question. :Saint Patrick said he would concede them the right every seventh year, when Saint Bridget threw her arms round his neck, and exclaimed, "Arrah, Pathrick, jewel, I daurn't go back to the girls wid such a proposal. Make it one year in four." Saint Patrick replied, "Bridget, acushla, squeeze me that way again, an' I'll give ye leap-year, the longest of the lot." Saint Bridget, upon this, popped the question to St Patrick himself, who, of course, could not marry: so he patched up the difficulty as best he could with a kiss and a silk gown. (Source: Evans, Ivor H, Brewer's Dictionary of Phrase and Fable, Cassell, London, 1988) According to a 1288 law in Scotland, fines were levied if the proposal was refused by the man; compensation ranged from a kiss to a silk gown to soften the blow. Because men felt that put them at too great a risk, the tradition was in some places tightened to restricting female proposals to 29 February.

Birthdays

A person who was born on 29 February may be called a "leapling". In non-leap years they usually celebrate their birthday on 28 February or 1 March. There are many instances in children's literature where a person's claim to be only a quarter of their actual age turns out be based on counting their leap-year birthdays. A similar device is used in the plot of the Gilbert and Sullivan operetta The Pirates of Penzance. Category:Calendars Category:Units of time als:Schaltjahr ko:윤년 ja:閏年 simple:Leap year th:ปีอธิกสุรทิน

Calendar year

According to the Gregorian calendar, the calendar year begins on January 1 and ends on December 31. Other alignments of the 12-month period can be used for purposes of accounting (see fiscal year). Generally speaking, a calendar year begins on the New Year's day of the given calendar system and ends on the day before the following New Year's day.

See also


- Calendar
- Year
- Seasonal year
- Fiscal year Category:Units of time th:ปีปฏิทิน

Seasonal year

The seasonal year is the time between successive recurrences of a seasonal event such as the flooding of a river, the migration of a species of bird, or the flowering of a species of plant. The need for farmers to predict seasonal events led to the development of calendars. However, the variability from year to year of seasonal events (due to climate change or just random variation) makes the seasonal year very hard to measure. This means that calendars are based on astronomical years (which are regular enough to be easily measured) as surrogates for the seasonal year. For example, the ancient Egyptians used the heliacal rising of Sirius to predict the flooding of the Nile. A study of temperature records over the past 300 years (David J. Thomson, SCIENCE, April 1995) suggests that the seasonal year is governed by the anomalistic year rather than the tropical year. This suggestion is surprising because the seasons have been thought to be governed by the tilt of the Earth's axis. The two types of years differ by a mere 4 days over 300 years, so Thompson's result may not be significant. However, the result is not unreasonable. The seasons can be considered to be an oscillating system driven by two inputs with slightly different frequencies: the total input of energy from the sun varies with the anomalistic year, while the distribution of this energy between the hemispheres varies with the tropical year. In other physical situtations, oscillating systems driven by two similar frequencies can latch onto either one. One point that must be considered is that the oscillation arising from the tilt of the axis is much greater than that arising from the distance of the sun. Category:Units of time

Intercalation

The solar year does not have whole number of days, but a calendar year must have a whole number of days. The only way to reconcile the two is to vary the number of days in the calendar year. In many calendars, this is done by adding to a common year of 365 days, an extra day (leap day or intercalary day): this makes a leap year of 366 days. In the Gregorian calendar, the intercalary day is February 29. The solar year does not have a whole number of lunar months either, so a lunisolar calendar must have a variable number of months in a year. This is usually 12 months, but sometimes a 13th month (an intercalary or embolismic month) is added to the year. ISO 8601 includes a specification for a 52-week year. Any year that has 53 Thursdays has 53 weeks; this extra week may be regarded as intercalary. The determination of whether a year has intercalation may be calculated (Julian, Gregorian and Hebrew calendars), or determined by observation (Iranian calendar).

See also


- Calendar
- Bahá'í calendar
- Julian calendar
- Gregorian calendar
- Iranian calendar
- Hebrew calendar
- Hindu calendar
- Chinese calendar
- Leap second Category:Calendars

Leap second

A leap second is an intercalary, one-second adjustment that keeps broadcast standards for time of day close to mean solar time. Leap seconds are used to keep time standards synchronized with civil calendars, the basis of which is astronomical. Broadcast standards for civil time are based on Coordinated Universal Time (UTC), which is maintained using extremely precise atomic clocks. In order to keep the UTC broadcast standard close to mean solar time, UTC is occasionally corrected by an intercalary adjustment, or "leap", of one (1) second. Over long time periods, leap seconds must be added at an ever increasing rate which corresponds to a parabola near 31 s/century² (see ΔT).

Reason for leap seconds

Traditionally, the second has been defined as 1/86400 of a mean solar day (see solar time). This is determined by the rotation of the Earth around its axis and its orbit around the Sun; time was measured by astronomical observations. The reason that we use leap seconds is that nowadays we measure time with stable atomic clocks (TAI or International Atomic Time), but the rotation of the Earth has been slowing down. The solar day gradually has become longer by about 1.7 ms every century, mainly due to the tidal acceleration of the Moon. The SI second that is counted by atomic time standards has been defined in such a way that its length matched the nominal second of 1/86400 of a mean solar day between 1750 and 1892. Since that time the length of the solar day has been slowly increasing. Therefore the time as measured by the rotation of the Earth has been accumulating a delay with respect to atomic time standards. From 1961 to 1971 the rate of atomic clocks was constantly slowed down in order to stay in sync with the rotation of the Earth (before 1961, broadcast time was synchronized to astronomically determined Greenwich Mean Time). From 1972 onwards, broadcast seconds have been exactly equal to the length of the SI second chosen in 1967 as a certain number of atomic vibrations. UTC is counted by atomic clocks, but is kept approximately in sync with UT1 (mean solar time) by introducing a leap second whenever necessary. This happens when the difference UT1−UTC is approaching 0.9 seconds, and is scheduled either between 30 June and 1 July of a year, or between 31 December of the current and 1 January of the next year. On January 1, 1972, the initial offset of UTC from TAI was chosen to be 10 seconds, which approximated the total difference which had accumulated between UT1 and TAI since 1958, when TAI was defined equal to UT1 (GMT). The table above shows the number of leap seconds added since then. The total difference between TAI and UTC is 10 seconds more than the total number of leap seconds. 1958 Take care not to confuse the small difference between the length of the mean solar day and the SI day, with the leap second adjustment of approximately 0.7 seconds per year. If Earth's rotation was slowing by the leap second amount, then the length of the solar day would have been 22 hours long 10,000 years ago. This erroneous line of reasoning confuses velocity with travelled distance (in time), and this fallacious argument has been used by some Creationists to claim that Earth is only a few thousand years old [http://www.talkorigins.org/indexcc/CE/CE011_1.html]. The correct reason for leap seconds is because the small difference between the length of the SI day and the mean solar day (currently about 0.002 seconds) adds up every day on the clocks that continuously count them. Note that the actual rotational period varies on unpredictable factors such as tectonic motion and has to be observed rather than computed. For example, assume you start counting the seconds from the Unix epoch of 12:00:00AM on January 1, 1970 with an atomic clock. At midnight on that day (as measured on UTC), your counter registers 0 seconds. After Earth has made one full rotation with respect to the mean Sun, your counter will register 86400.002 (once again, the precise value will vary) seconds. Based on your counter, you can calculate that the date is 12:00:00AM on January 2, 1970 UT1. After exactly 500 rotations, your counter will register 43,200,001 seconds. Since 86400 × 500 is 43,200,000 seconds, you will calculate that the date is 12:00:01AM on May 16, 1971 (exactly 500 days after January 1, 1970) as measured in atomic time (UTC), while it is only 12:00:00AM on May 16, 1971 in solar time (UT1). If you had added a leap second on December 31, 1970 to your counter, then the counter would have a value of 43,200,001 seconds at midnight on May 16, 1971 and allow you to calculate the correct date. The actual system involving leap seconds was set up to allow TAI and UT1 to have an offset of 0 seconds on January 1, 1958. While tidal braking will slow down Earth's rotation, this will cause the amount of SI seconds in a mean solar day to increase from approximately 86400.002 to 86400.005 over the course of 100 years.

Announcement of leap seconds

The announcement to insert a leap second is usually issued whenever the difference between UTC and UT1 approaches 0.7s, to keep the difference between UTC and UT1 from exceeding ±0.9 s. After UTC 23:59:59, a positive leap second at 23:59:60 would be counted, before the clock indicates 00:00:00 of the next day. Negative leap seconds are also possible should the Earth's rotation become slightly faster; in that case, 23:59:58 would be followed by 00:00:00. Leap seconds occur only at the end of a UTC month, and have only ever been inserted at the end of June 30 or December 31. Unlike leap days, they occur simultaneously worldwide; for example, a leap second on 31 December will be observed as 6:59:60 pm U.S. Eastern Standard Time. It is the responsibility of the International Earth Rotation and Reference Systems Service (IERS) to measure the Earth's rotation and determine whether a leap second is necessary. Their determination is announced in Bulletin C, typically published every six months. Historically, leap seconds have been inserted about every 18 months. However, the Earth's rotation rate is unpredictable in the long term, so it is not possible to predict the need for them more than six months in advance. Between January 1972 and December 1998, the IERS gave instructions to insert a leap second on 22 occasions. The interval between 1998-12-31 and 2005-12-31, the most recent leap second, is the longest period since the system was introduced without a leap second. Note that leap seconds have nothing to do with leap years.

Proposal to redefine UTC and abolish leap seconds

July 5, 2005, the Head of the Earth Orientation Center of the IERS sent a notice to IERS Bulletins C and D subscribers, soliciting comments on a proposal before the ITU-R Study Group 7's WP7-A to eliminate leap seconds from the UTC broadcast standard before 2008. (The ITU-R is responsible for the definition of UTC). The Wall Street Journal noted that the proposal was considered by a US official to be a private matter internal to the ITU as of July, 2005. It is expected to be considered in November, 2005. Under the proposal, leap seconds would be technically replaced by leap hours as an attempt to satisfy the legal requirements of several ITU-R member nations that civil time be astronomically tied to the Sun. Many commentors consider the proposal to be flawed in many ways.
- Little justification for changing UTC has been presented.
- No serious analysis of the costs of the change (or not making a change) has been attempted.
- The meaning of the term UTC in existing documents (technical and legal) and existing software will become ambiguous. All references to UTC will have to be reviewed to ascertain whether the original intent was to be mean solar time or to be atomic time or simply to be the conventional civil time scale which happens to be in current use.
- All reported surveys inquiring about a change to UTC produced results which did not indicate that any change was desired.
- There is an existing standard time scale, International Atomic Time AKA TAI, for systems which prefer to avoid leap seconds.
- The time indicated by sundials would no longer bear a fixed relation to civil time, but
  - United States Federal Law indicates that the legal time of the US is based on mean solar time.
  - The CGPM (general congress of weights and measures, the international force behind the SI) recommendation to use UTC is predicated on the fact that the leaps keep it reasonably close to mean solar time.
- When the proponents convened an international colloquium in 2003 they were told not to change UTC (because that would confuse everyone about its meaning), but to define a new time scale whose purpose was to serve their needs. They were also told that leap hours were not acceptable.
- The process of discussing the proposals has been mostly shrouded in secrecy for years. Relevant ITU documents and meetings are not publically available. On the other (pro) side of the discussion are several arguments. Some of these have only become relevant with the recent wide-spread proliferation of computers using UTC as their internal time representation. For example, as things presently stand, it is not possible to correctly compute the elapsed interval between two stated instants of UTC without consulting manually updated and maintained tables of when leap seconds have occured. Moreover, it is not possible even in theory to compute such time intervals for instants more than about six months in the future. This is not a matter of computer programmers being "lazy"; rather, the uncertainty of leap seconds introduces to those applications needing accurate notions of elapsed time intervals either fundamentally new (and often untenable) operational burdens for computer systems (the need to be online and do lookups) or unsurmountable theoretical concerns (the inability in a UTC-based computer to accurately schedule any event more than six months in the future).

References


- Ahuja, Anjana (Oct. 30, 2005). "Savouring the last leap second in history". New Straits Times, p. F10.
- Grossman, Wendy M. (Nov. 2005). "Wait a Second". Scientific American, p. 12–13.

External links


- [http://hpiers.obspm.fr/eop-pc/earthor/utc/leapsecond.html UTC vs UT1 1972–2005]
- [http://hpiers.obspm.fr/iers/bul/bulc/bulletinc.dat IERS Bulletin C, where leap seconds are announced]
- [http://hpiers.obspm.fr/eoppc/bul/bulc/BULLETINC.GUIDE IERS information about Bulletin C and when leap seconds may occur]
- [http://www.iers.org/iers/earth/rotation/utc/table2.html IERS Archive, to view old announcements]
- [http://tycho.usno.navy.mil/leapsec.html USNO article on leap seconds]
- [http://www.meinberg.de/english/info/leap-second.htm Leap Seconds in NTP, GPS, DCF77]
- [http://www.leapsecond.com/java/gpsclock.htm Dynamic differences between UTC and TAI]
- [http://www.leapsecond.com/notes/leap-watch.htm How to Watch a Leap Second]
- [http://www.npr.org/templates/story/story.php?storyId=4734092 The Year 2005 to Have 'Leap Second' Added, NPR audio segment by Joe Palca]

Should UTC be redefined and/or should leap seconds go away?


- [http://www.post-gazette.com/pg/05210/545823.stm Why the US wants to end link between time and sun] - Wall Street Journal article
- [http://www.cl.cam.ac.uk/~mgk25/time/metrologia-leapsecond.pdf The leap second: its history and possible future] - R A Nelson et al, Metrologia, 2001
- [http://www.ucolick.org/~sla/leapsecs/ UTC might be redefined without Leap Seconds] - extensive references by Steve Allen at Lick Observatory
- [http://www.ucolick.org/~sla/leapsecs/nc1985wp7a.html Summary of the US Working Group proposal] and brief responses
- [http://igscb.jpl.nasa.gov/mail/igsmail/2005/msg00114.html Opposition to the change from Kenneth Seidelmann] - a member of the US Working Party 7A (USWP7A)
- [http://www.cl.cam.ac.uk/~mgk25/time/leap/ Efforts to abolish leap seconds] from Markus Kuhn
- [http://rom.usno.navy.mil/archives/leapsecs.html the LEAPSECS mailing list] - archive and joining info Category:Timekeeping ja:閏秒

February

February is the second month of the year in the Gregorian Calendar. It is the shortest Gregorian month and the only month with the length of 28 or 29 days. The month has 29 days in leap years, when the year number is divisible by four (except for years that are divisible by 100 and not by 400). In other years the month has 28 days. February begins, astronomically speaking, with the sun in the constellation of Capricornus and ends with the sun in the constellation of Aquarius. Astrologically speaking, February begins with the sun in the sign of Aquarius and ends in the sign of Pisces. February was named for the Roman god Februus, the god of purification. January and February were the last two months to be added to the Roman calendar, since the Romans originally considered winter a monthless period. This change was made by Numa Pompilius about 700 BC in order to bring the calendar in line with a standard lunar year. Numa's Februarius contained 29 days (30 in a leap year). Augustus is alleged to have removed one day from February and added it to August, (renamed from Sextilis to honor himself), so that Julius Caesar's July would not contain more days. However there is little historical evidence to support this claim. July February was nominally the last month of the Roman calendar, as the year originally began in March. At certain intervals Roman priests inserted an intercalary month, Mercedonius, after February to realign the year with the seasons. Historical names for February include the Anglo-Saxon terms Solmoneth (mud month) and Kale-monath (named for cabbage) as well as Charlemagne's designation Hornung. In old Japanese calendar, the month is called Kisaragi (如月, 絹更月 or 衣更月). It is sometimes also called Mumetsuki (梅見月) or Konometsuki (木目月). In Finnish, the month is called helmikuu, meaning "month of the pearl". "February" is pronounced without the first r, as "Febuary", by many speakers. This is probably dissimilation, or an analogical change influenced by "January".

See also


- Historical anniversaries

External links


- [http://www.straightdope.com/classics/a2_160.html The Straight Dope: How come February has only 28 days?] Category:Months ko:2월 ms:Februari ja:2月 simple:February th:กุมภาพันธ์

March 21

March 21 is the 80th day of the year in the Gregorian Calendar (81st in leap years). It is also the first day of the astrological year. There are 285 days remaining.

Events


- 1556 - In Oxford, Archbishop of Canterbury Thomas Cranmer is burned at the stake.
- 1788 - A fire destroys 856 buildings in New Orleans and leaves most of the town in ruins.
- 1800 - With the church leadership driven out of the Rome during an armed conflict, Pius VII was crowned Pope in Venice with a temporary papal tiara made of papier-mâché.
- 1801 - The Battle of Alexandria was fought between British and French forces near the ruins of Nicopolis in Egypt.
- 1804 - Code Napoléon was adopted as French civil law.
- 1857 - Earthquake in Tokyo, Japan kills over 100,000.
- 1871 - Journalist Henry Morton Stanley began his trek to find the missionary and explorer David Livingstone.
- 1919 - The Chinese High School is established in Singapore by Tan Kah Kee.
- 1918 - World War I: Second Battle of the Somme begins
- 1928 - Charles Lindbergh is presented the Congressional Medal of Honor for his first trans-Atlantic flight.
- 1935 - Shah Reza Pahlavi formally asked the international community to call Persia by its native name, Iran, which means 'Land of the Aryans'.
- 1940 - Paul Reynaud becomes Prime Minister of France
- 1945 - World War II: British troops liberate Mandalay, Burma
- 1952 - Alan Freed presents the Moondog Coronation Ball, the first rock and roll concert, in Cleveland, Ohio
- 1960 - Apartheid: Massacre in Sharpeville, South Africa: Police open fire on a group of unarmed black South African demonstrators, killing 69 and wounding 180
- 1963 - Alcatraz, a federal penitentiary on an island in San Francisco Bay, closes.
- 1964 - In Copenhagen, Denmark, Gigliola Cinquetti wins the ninth Eurovision Song Contest for Italy singing "Non ho l'età" (I'm not old enough).
- 1965 - Ranger program: NASA launches Ranger 9 which is the last in a series of unmanned lunar space probes.
- 1965 - Martin Luther King Jr leads 3,200 people on the start of the third and finally successful civil rights march from Selma to Montgomery Alabama.
- 1970 The first Earth Day proclamation was issued by San Francisco Mayor Joseph Alioto.
- 1970 - Vinko Bogataj crashes during a ski-jumping championship in Germany; his image becomes that of the "agony of defeat guy" in the opening credits of ABC's Wide World of Sports.
- 1970 - In Amsterdam, Netherlands, Dana wins the fifteenth Eurovision Song Contest for Ireland singing "All Kinds of Everything".
- 1980 - President Jimmy Carter announces a United States boycott of the 1980 Summer Olympics in Moscow to protest the Soviet Invasion of Afghanistan.
- 1980 - On the season finale of the soap opera Dallas, the infamous character J.R. Ewing is shot by an unseen assailant, leading to the catchphrase "Who Shot JR?"
- 1985 - Canadian paraplegic athlete and humanitarian Rick Hansen begins his circumnavigation in a wheelchair in the name of spinal cord injury medical research.
- 1989 - Sports Illustrated reports allegations that tie baseball player Pete Rose to baseball gambling.
- 1990 - Namibia becomes independent after 75 years of South African rule.
- 1999 - Bertrand Piccard and Brian Jones become the first to circumnavigate the Earth in a hot air balloon.
- 2002 - In Pakistan, Ahmed Omar Saeed Sheikh along with three other suspects are charged with murder for their part in the kidnapping and killing of Wall Street Journal reporter Daniel Pearl.
- 2004 - In Malaysia, the 11th Federal and State elections are held, returning the ruling coalition Barisan Nasional to power with an increased majority.
- 2005 - In Red Lake, Minnesota, 10 are killed in a school shooting, the worst since the Columbine High School massacre.

Births


- 1521 - Maurice, Elector of Saxony (d. 1553)
- 1527 - Hermann Finck, German composer (d. 1558)
- 1685 - Johann Sebastian Bach, German composer (d. 1750)
- 1713 - Francis Lewis, American signer of the Declaration of Independence (d. 1803)
- 1763 - Jean Paul, German writer (d. 1825)
- 1768 - Joseph Fourier, French mathematician (d. 1830)
- 1806 - Benito Juárez, Mexican statesman and national hero (d. 1872)
- 1839 - Modest Petrovich Mussorgsky, Russian composer (d. 1881)
- 1869 - Florenz Ziegfeld, theatrical producer (d. 1932)
- 1876 - John Tewksbury, American athlete (d. 1968)
- 1882 - Gilbert M. 'Broncho Billy' Anderson, American actor (d. 1971)
- 1895 - Zlatko Baloković, Croatian violinist (d. 1955)
- 1901 - Karl Arnold, German politician (d. 1958)
- 1902 - Son House, American musician (d. 1988)
- 1904 - Forrest Mars Sr., American candymaker (d. 1999)
- 1906 - Jim Thompson, American designer and businessman
- 1913 - George Abecassis, English race car driver (d. 1991)
- 1920 - Georg Ots, Estonian singer (d. 1975)
- 1921 - Arthur Grumiaux, Belgian violinist (d. 1986)
- 1922 - Russ Meyer, American film director and producer (d. 2004)
- 1923 - Shri Mataji Nirmala Shrivastava, Indian founder of Sahaja Yoga
- 1927 - Hans-Dietrich Genscher, German politician
- 1932 - Walter Gilbert, American chemist, Nobel Prize laureate
- 1932 - Joseph Silverstein, American violinist and conductor
- 1930 - James Coco, American actor (d. 1987)
- 1934 - Al Freeman, Jr., American actor
- 1935 - Brian Clough, English footballer and football manager (d. 2004)
- 1940 - Solomon Burke, American singer
- 1943 - Vivian Stanshall, British musician (Bonzo Dog Doo-Dah Band)
- 1945 - Rose Stone, American musician (Sly & the Family Stone)
- 1946 - Timothy Dalton, British actor
- 1956 - Ingrid Kristiansen, Norwegian runner
- 1958 - Sabrina Le Beauf, American actress
- 1958 - Gary Oldman, English actor
- 1959 - Nobuo Uematsu, Japanese composer
- 1960 - Ayrton Senna, Brazilian race car driver (d. 1994)
- 1961 - Lothar Matthäus, German footballer
- 1962 - Matthew Broderick, American actor
- 1962 - Rosie O'Donnell, American comedienne, actress, talk show host, and publisher
- 1963 - Ronald Koeman, Dutch footballer and football manager
- 1967 - Jonas "Joker" Berggren, Swedish musician (Ace of Base)
- 1975 - Justin Pierce, British actor (d. 2000)
- 1975 - Mark Williams, Welsh snooker player
- 1976 - Liza Harper, French actress
- 1977 - DJ Premier, American rapper (Gang Starr)
- 1980 - Ronaldinho, Brazilian footballer
- [[1980{months

21 March

March 21 is the 80th day of the year in the Gregorian Calendar (81st in leap years). It is also the first day of the astrological year. There are 285 days remaining.

Events


- 1556 - In Oxford, Archbishop of Canterbury Thomas Cranmer is burned at the stake.
- 1788 - A fire destroys 856 buildings in New Orleans and leaves most of the town in ruins.
- 1800 - With the church leadership driven out of the Rome during an armed conflict, Pius VII was crowned Pope in Venice with a temporary papal tiara made of papier-mâché.
- 1801 - The Battle of Alexandria was fought between British and French forces near the ruins of Nicopolis in Egypt.
- 1804 - Code Napoléon was adopted as French civil law.
- 1857 - Earthquake in Tokyo, Japan kills over 100,000.
- 1871 - Journalist Henry Morton Stanley began his trek to find the missionary and explorer David Livingstone.
- 1919 - The Chinese High School is established in Singapore by Tan Kah Kee.
- 1918 - World War I: Second Battle of the Somme begins
- 1928 - Charles Lindbergh is presented the Congressional Medal of Honor for his first trans-Atlantic flight.
- 1935 - Shah Reza Pahlavi formally asked the international community to call Persia by its native name, Iran, which means 'Land of the Aryans'.
- 1940 - Paul Reynaud becomes Prime Minister of France
- 1945 - World War II: British troops liberate Mandalay, Burma
- 1952 - Alan Freed presents the Moondog Coronation Ball, the first rock and roll concert, in Cleveland, Ohio
- 1960 - Apartheid: Massacre in Sharpeville, South Africa: Police open fire on a group of unarmed black South African demonstrators, killing 69 and wounding 180
- 1963 - Alcatraz, a federal penitentiary on an island in San Francisco Bay, closes.
- 1964 - In Copenhagen, Denmark, Gigliola Cinquetti wins the ninth Eurovision Song Contest for Italy singing "Non ho l'età" (I'm not old enough).
- 1965 - Ranger program: NASA launches Ranger 9 which is the last in a series of unmanned lunar space probes.
- 1965 - Martin Luther King Jr leads 3,200 people on the start of the third and finally successful civil rights march from Selma to Montgomery Alabama.
- 1970 The first Earth Day proclamation was issued by San Francisco Mayor Joseph Alioto.
- 1970 - Vinko Bogataj crashes during a ski-jumping championship in Germany; his image becomes that of the "agony of defeat guy" in the opening credits of ABC's Wide World of Sports.
- 1970 - In Amsterdam, Netherlands, Dana wins the fifteenth Eurovision Song Contest for Ireland singing "All Kinds of Everything".
- 1980 - President Jimmy Carter announces a United States boycott of the 1980 Summer Olympics in Moscow to protest the Soviet Invasion of Afghanistan.
- 1980 - On the season finale of the soap opera Dallas, the infamous character J.R. Ewing is shot by an unseen assailant, leading to the catchphrase "Who Shot JR?"
- 1985 - Canadian paraplegic athlete and humanitarian Rick Hansen begins his circumnavigation in a wheelchair in the name of spinal cord injury medical research.
- 1989 - Sports Illustrated reports allegations that tie baseball player Pete Rose to baseball gambling.
- 1990 - Namibia becomes independent after 75 years of South African rule.
- 1999 - Bertrand Piccard and Brian Jones become the first to circumnavigate the Earth in a hot air balloon.
- 2002 - In Pakistan, Ahmed Omar Saeed Sheikh along with three other suspects are charged with murder for their part in the kidnapping and killing of Wall Street Journal reporter Daniel Pearl.
- 2004 - In Malaysia, the 11th Federal and State elections are held, returning the ruling coalition Barisan Nasional to power with an increased majority.
- 2005 - In Red Lake, Minnesota, 10 are killed in a school shooting, the worst since the Columbine High School massacre.

Births


- 1521 - Maurice, Elector of Saxony (d. 1553)
- 1527 - Hermann Finck, German composer (d. 1558)
- 1685 - Johann Sebastian Bach, German composer (d. 1750)
- 1713 - Francis Lewis, American signer of the Declaration of Independence (d. 1803)
- 1763 - Jean Paul, German writer (d. 1825)
- 1768 - Joseph Fourier, French mathematician (d. 1830)
- 1806 - Benito Juárez, Mexican statesman and national hero (d. 1872)
- 1839 - Modest Petrovich Mussorgsky, Russian composer (d. 1881)
- 1869 - Florenz Ziegfeld, theatrical producer (d. 1932)
- 1876 - John Tewksbury, American athlete (d. 1968)
- 1882 - Gilbert M. 'Broncho Billy' Anderson, American actor (d. 1971)
- 1895 - Zlatko Baloković, Croatian violinist (d. 1955)
- 1901 - Karl Arnold, German politician (d. 1958)
- 1902 - Son House, American musician (d. 1988)
- 1904 - Forrest Mars Sr., American candymaker (d. 1999)
- 1906 - Jim Thompson, American designer and businessman
- 1913 - George Abecassis, English race car driver (d. 1991)
- 1920 - Georg Ots, Estonian singer (d. 1975)
- 1921 - Arthur Grumiaux, Belgian violinist (d. 1986)
- 1922 - Russ Meyer, American film director and producer (d. 2004)
- 1923 - Shri Mataji Nirmala Shrivastava, Indian founder of Sahaja Yoga
- 1927 - Hans-Dietrich Genscher, German politician
- 1932 - Walter Gilbert, American chemist, Nobel Prize laureate
- 1932 - Joseph Silverstein, American violinist and conductor
- 1930 - James Coco, American actor (d. 1987)
- 1934 - Al Freeman, Jr., American actor
- 1935 - Brian Clough, English footballer and football manager (d. 2004)
- 1940 - Solomon Burke, American singer
- 1943 - Vivian Stanshall, British musician (Bonzo Dog Doo-Dah Band)
- 1945 - Rose Stone, American musician (Sly & the Family Stone)
- 1946 - Timothy Dalton, British actor
- 1956 - Ingrid Kristiansen, Norwegian runner
- 1958 - Sabrina Le Beauf, American actress
- 1958 - Gary Oldman, English actor
- 1959 - Nobuo Uematsu, Japanese composer
- 1960 - Ayrton Senna, Brazilian race car driver (d. 1994)
- 1961 - Lothar Matthäus, German footballer
- 1962 - Matthew Broderick, American actor
- 1962 - Rosie O'Donnell, American comedienne, actress, talk show host, and publisher
- 1963 - Ronald Koeman, Dutch footballer and football manager
- 1967 - Jonas "Joker" Berggren, Swedish musician (Ace of Base)
- 1975 - Justin Pierce, British actor (d. 2000)
- 1975 - Mark Williams, Welsh snooker player
- 1976 - Liza Harper, French actress
- 1977 - DJ Premier, American rapper (Gang Starr)
- 1980 - Ronaldinho, Brazilian footballer
- [[1980{months

Roman calendar

The Roman calendar changed its form several times in the time between the foundation of Rome and the fall of the Roman Empire. This article generally discusses the early Roman or 'pre-Julian' calendars. The calendar used after 46 BC is discussed under the Julian calendar. Julian calendar and Sextilis, and allows for the insertion of an intercalary lunar month.]]

History of the Calendar

To begin with it was a lunar calendar containing ten months, starting at the vernal equinox, traditionally invented by Romulus, the founder of Rome about 753 BC. However it seems to have been based on the Greek lunar calendar. The months at this time were
- Martius (31 days)
- Aprilis (30 days)
- Maius (31 days)
- Junius (30 days)
- Quintilis (31 days)
- Sextilis (30 days)
- September (30 days)
- October (31 days)
- November (30 days) and
- December (30 days) Thus the calendar year lasted 304 days and there were about 61 days of winter that did not fall within the calendar. The first reform of the calendar was attributed to Numa Pompilius, the second of the seven traditional Kings of Rome. He is said to have reduced the 30-day months to 29 days and to have added January (29 days) and February (28 days) to the end of the calendar around 713 BC, and thus brought the length of the calendar year up to 355 days:
- Martius (31 days)
- Aprilis (29 days)
- Maius (31 days)
- Iunius (29 days)
- Quintilis (31 days)
- Sextilis (29 days)
- September (29 days)
- October (31 days)
- November (29 days)
- December (29 days)
- Ianuarius (29 days)
- Februarius (28 days) In order to keep the calendar year roughly aligned with the solar year, a leap month of 27 days, the Mensis Intercalaris, sometimes also known as Mercedonius or Mercedinus, was added from time to time at the end of February, which was shortened to 23 or 24 days. The resulting year was either 377 or 378 days long. The decision to insert the intercalary month, and its placement, was the responsibility of the pontifex maximus. On average, this happened roughly in alternate years. The system of aligning the year through intercalary months broke down at least twice. The first time was during and after the Second Punic War. It led to the reform of the Lex Acilia in 191 BC. The details of this reform are unclear, but it appears to have successfully regulated intercalation for over a century. The second breakdown was in the middle of the first century BC. This breakdown may have been related to the increasingly chaotic and adversarial nature of Roman politics at the time. The position of pontifex maximus was not a full-time job; it was held by a member of the Roman elite, who would almost invariably be involved in the machinations of Roman politics. Because a Roman calendar year defined the term of office of elected Roman magistrates, a pontifex maximus would have reason to lengthen a year in which he or his allies were in power, or to not lengthen a year in which his political opponents held office. It was only after Julius Caesar, who had been pontifex maximus for some years, seized absolute power that the calendar was overhauled, with the result being the Julian calendar.

Months

The Romans had special names for 3 specific days in each month. The system was originally based on phases of the Moon (Luna), and these days were probably declared when the lunar conditions were right. After the reforms of Numa Pompilius, they occurred on fixed days.
- Kalends - first day of the month, from which the word "calendar" is derived. Interest on debt was due on Kalends.
- Nones – depending on the month, could be the 5th or the 7th day; traditionally the day of the Half Moon
- Ides – depending on the month, could be the 13th or the 15th day; traditionally the day of the Full Moon :Months with Ides and Nones occurring on the 13th/5th day: January, February, April, June, August, September, November, December :Months with Ides and Nones occurring on the 15th/7th day: March, May, July, October -- :a mnemonic: ::In March, July, October, May ::The IDES fall on the fifteenth day; ::The NONES the seventh; but all besides ::Have two days less for Nones and Ides. Days were numbered in a way that is quite different from the modern Western calendar. The Romans did not count the days of the month retrospectively, looking back to the first of the month (that is: 1st, 2nd day since the start of the month, 3rd day since the start of the month). They counted forward to their named days. Also, to the distress of moderns trying to work out dates in Roman calendar documents, they counted inclusively, so that 2 September is considered 4 days before 5 September, rather than 3 days before.

The example of September

The following example spells out how days were named for the pre-Julian September, which had only 29 days. It shows the Roman form of the date, the translation, and how we would say it today. The Romans used abbreviations: "a.d." = "ante diem" = "day before", "prid." = "pridie" = "the day before", "Kal" = "Kalends" etc. :Kal. Sept. = Kalends of September = 1 September :a.d. IV Non. Sept. = 4 days before the Nones of September = 2 September :a.d. III Non. Sept. = 3 days before the Nones of September = 3 September :prid. Non. Sept. = the day before the Nones of September = 4 September :Non. Sept. = Nones of September = 5 September :a.d. VIII Id. Sept. = 8 days before the Ides of September = 6 September :a.d. VII Id. Sept. = 7 days before the Ides of September = 7 September and so on till :a.d. III Id. Sept. = 3 days before the Ides of September = 11 September :prid. Id. Sept. = the day before the Ides of September = 12 September :Id. Sept. = Ides of September = 13 September :a.d. XVII Kal. Oct. = 17 days before the Kalends of October = 14 September :a.d. XVI Kal. Oct. = 16 days before the Kalends of October = 15 September and so on till :a.d. III Kal. Oct. = 3 days before the Kalends of October = 28 September :prid. Kal. Oct. = the day before the Kalends of October = 29 September :Kal. Oct. = Kalends of October = 1 October Notice that by counting inclusively and by having a special name for the day before a named day the Roman calendar loses the possibility of saying: 2 days before a named day. Also, after the Ides, the date no longer mentions September, but is counting down towards October. When Julius Caesar added a day to September, he didn't add it to the end of the month. Rather, the new day that got added was the day after the Ides: :a.d. XVIII Kal. Oct. = 18 days before the Kalends of October = 14 September As a result, the position of all the following dates in September got bumped up by one day. This has some unexpected effects. For example, the emperor Augustus was born on 23 September 63 BC. In the pre-Julian calendar this is 8 days before the Kalends of October (or, in Roman style, a.d. VIII Kal. Oct.), but in the Julian calendar it is 9 days (a.d. IX Kal. Oct.). Because of this ambiguity, in some parts of the Empire his birthday was celebrated on both dates, i.e. (for us) on both 23 and 24 September.

Days of the week

The Roman Republic, like the Etruscans, used a "market week" of eight days, marked as A to H in the calendar. A market was held on the eighth day. For the Romans, who counted inclusively, this was every ninth day, hence the market became called "nundinae". Since the length of the year was not a multiple of 8 days, the letter for the market day (known as a "nundinal letter") changed every year. For example, if the current letter for market days was A and the year was 355 days long, then the letter for the next year would be F. The market cycle was a fundamental rhythm of daily life, and the market day was the day that country people would come to the city. For this reason, a law was passed in 287 BC (the Lex Hortensia) that forbade the holding of meetings of the comitia (for example to hold elections) on market days, but permitted the holding of legal actions. In the late republic, a superstition arose that it was unlucky to start the year with a market day (i.e. for the market day to fall on 1 January, with a letter A), and the pontiffs, who regulated the calendar, took steps to avoid it. Because the market cycle was absolutely fixed at 8 days under the Republic, information about the dates of market days is one of the most important tools we have for working out the Julian equivalent of a Roman date in the pre-Julian calendar. In the early Empire, the Roman market day was occasionally changed. The details of this are not clear, but one likely explanation is that it would be moved by one day if it fell on the same day as the festival of Regifugium, an event that could occur every other Julian leap year. When this happened the market day would be moved to the next day, which was the bissextile (leap) day. The modern seven-day week came into use during the early imperial period, after the Julian calendar came into effect, apparently stimulated by immigration from the Roman East. For a while it coexisted alongside the old 8-day nundinal cycle, and fasti are known which show both cycles. It was finally given official status by Constantine in 321. The days of the week were dedicated to the seven planets. They were (note the similarities of some of the days with French and Spanish and other Romance languages):
- Sunday – Dies Solis (day of the sun)
- Monday – Dies Lunae (day of the moon)
- Tuesday – Dies Martis (day of Mars)
- Wednesday – Dies Mercuri (day of Mercury)
- Thursday – Dies Iovis (day of Jupiter)
- Friday – Dies Veneris (day of Venus)
- Saturday – Dies Saturni (day of Saturn)

Character of the Day

An aspect of the Roman calendar that is quite unfamiliar to us is that each day had a "character", which was marked in the fasti. The most important of these were dies fasti, marked by an F, on which legal matters could normally be heard, dies nefasti, marked by an N, on which they could not, and dies comitiales, marked by a C, on which meetings of the public assemblies known as comitia were permitted, subject to other constraints such as the Lex Hortensia. A few days had a different character, e.g. EN (endotercissus or perhaps endoitio exitio nefas), a day in which legal actions were permitted on half of the day only, and NP, which were public holidays.

Years

In the Roman Republic, the years were not counted. Instead they were named after the consuls who were in power at the beginning of the year (see List of Republican Roman Consuls). For example, 205 BC was The year of the consulship of Publius Cornelius Scipio Africanus and Publius Licinius Crassus. However, in the later Republic, historians and scholars began to count years from the founding of the city of Rome. Different scholars used different dates for this event. The date most widely used today is that calculated by Varro, 753 BC, but other systems varied by up to several decades. Dates given by this method are numbered ab urbe condita (meaning after the founding of the city, and abbreviated AUC). When reading ancient works using AUC dates, care must be taken to determine the epoch used by the author before translating the date into a Julian year. The first day of the consular term, which was effectively the first day of the year, changed several times during Roman history. It became 1 January in 153 BC. Before then it was 15 March. Earlier changes are a little less certain. There is good reason to believe it was 1 May for most of the third century BC, till 222 BC. Livy mentions consulates starting on 1 July before then, and arguments exist for other dates at earlier times.

Converting Pre-Julian Dates

Finding the Julian equivalent of a Roman date can be quite tricky. Even early Julian dates, before the leap year cycle was stabilised, are not quite what they appear to be. For example, it is well known that Julius Caesar was assassinated on the Ides of March in 44 BC, and this is usually converted to 15 March 44 BC. While he was indeed assassinated on the 15th day of the Roman month Martius, the equivalent date on the modern Julian calendar is probably 14 March 44 BC. Finding the exact Julian equivalent of a pre-Julian date is much harder. Since we have an essentially complete list of the consuls, it is not difficult to find the Julian year that generally corresponds to a pre-Julian year. However, our sources very rarely tell us which years were regular, which were intercalary, and how long an intercalary year was. For this reason, pre-Julian dates can be very misleading. We do have a number of clues to help us. First, we know when the Julian calendar began, although there is some argument about it. We have detailed sources for the previous decade or so, mostly in the letters and speeches of Cicero. Combining these with what we know about how the calendar worked, especially the nundinal cycle, we can accurately convert Roman dates after 58 BC. Also, the histories of Livy give us exact Roman dates for two eclipses in 190 BC and 168 BC, and we have a few loose synchronisms to dates in other calendars which help to give rough (and sometimes exact) solutions for the intervening period. Before 190 BC the alignment between the Roman and Julian years is determined by clues such as the dates of harvests mentioned in the sources. This allows us to estimate approximate Julian equivalents of Roman dates back to the start of the First Punic War in 264 BC. However, the number of years before 45 BC for which we can accurately and precisely convert Roman dates to Julian dates is very small.

See also


- Calendar
- Fasti
- Julian calendar
- Ancient Rome

References


- Plutarch - Numa Pompilius
- Ovid - Fasti
- Bickerman, E.J. Chronology of the Ancient World. London: Thames & Hudson, 1969, rev. ed. 1980.
- Michels, A. K. The Calendar of the Roman Republic Princeton, 1967

External links


- [http://www.12x30.net/linked.html Bill Hollon's site]
- [http://webexhibits.org/calendars/calendar-roman.html Early Roman Calendar - History]
- [http://penelope.uchicago.edu/Thayer/E/Roman/Texts/secondary/SMIGRA
- /Calendarium.html Smith's Dictionary article]
- [http://www.tyndale.cam.ac.uk/Egypt/ptolemies/chron/roman/chron_rom_intro.htm Roman Dates (Chris Bennett's site)]
- [http://penelope.uchicago.edu/~grout/encyclopaedia_romana/calendar/romancalendar.html James Grout: The Roman Calendar, part of the Encyclopædia Romana]
- ja:ローマ暦

Lunar calendar

A lunar calendar is a calendar whose date indicates the moon phase. This is normally done by having a month which corresponds to a lunation so that the day of month indicates the moon phase. If a calendar tracks the seasons, it is also a lunisolar calendar.

Examples

Most lunar calendars are also lunisolar, such as the Hebrew, Chinese and Hindu calendar, and most calendar systems used in antiquity. The reason for this is that a year is not evenly divisible by an exact number of lunations, so without any correction the seasons will drift with respect to the calendar year. The only widely used purely lunar calendar is the Islamic calendar, which always consists of 12 lunations. As a result of this, it is mostly used for religious purposes, alongside a secular solar calendar, and Islamic feasts perform a full circle with respect to the seasons every 33 years.

Determining the start of the month

Since the length of a month is difficult to predict and varies from its average value, many lunar calendars are based on first sighting of the lunar crescent, or astronomically determining the conjunction of the sun and the moon. Because observations are subject to uncertainty and weather conditions, and astronomical methods are highly complex, there have been attempts to create fixed arithmetical rules. The average length of the synodic month is 29.530589 days. This means the length of a month is alternately 29 and 30 days (termed respectively hollow and full). The distribution of hollow and full months can be determined using continued fractions, and examining successive approximations for the length of the month in terms of fractions of a day. In the list below, after the number of days listed in the numerator, an integer number of months as listed in the denominator have been completed: 29 / 1 30 / 1 59 / 2 (error: 1 day after about 33 months) 443 / 15 (error: 1 day after about 30 years) 502 / 17 (error: 1 day after about 70 years) 1447 / 49 (error: 1 day after about 3 millennia) 25101 / 850 (error: dependent on change of synodic month value{{{

5th century BC

(2nd millennium BC - 1st millennium BC - 1st millennium) ----

Overview

The 5th and 6th centuries BC are a period of philosophical brilliance among advanced civilizations. Ancient Greek philosophy develops during the 5th century BC, setting the foundation for Western ideology.

Events


- Demotic becomes the dominant script of ancient Egypt
- Persians invade Greece twice (Persian Wars)
- Battle of Marathon (490)
- 486 BCE First Buddist Council at Rejgaha, under the patronage of King Ajatasattu. Oral tradition established for the first time.

Significant persons


- Pythagoras of Samos, Greek mathematician. See Pythagorean theorem. (582 - 496 BC).
- Gautama Buddha, founding figure of Buddhism (ca. 563 - 483 BC).
- Confucius, founding figure of Confucianism (551 - 479 BC).
- Aeschylus of Athens, playwright (525 - 456 BC).
- Darius I, King of Persia (reigned 521 - 485 BC).
- Sophocles of Athens, playwright (496 - 406 BC).
- Pericles of Athens, politician (ca. 495 - 429 BC).
- Herodotus of Halicarnassus, historian (ca. 485 BC).
- Euripides of Athens, playwright (ca. 480 - 406 BC).
- Socrates of Athens, philosopher (470 - 399 BC).
- Aristophanes of Athens, playwright (ca. 446 - 385 BC).
- Darius II, king of Persia (reigned 423-404 BC)
- Ezra and Nehemiah active in Judea.
- Tollund Man, Human sacrifice victim on the Jutland Peninsula in Denmark, possibly the earliest known evidence for worship of Odin.
- Empedocles

Inventions, discoveries, introductions


- Cast iron is first used in Wu.

Decades and years

Category:5th century BC ko:기원전 5세기 ja:紀元前5世紀

24 February

February 24 is the 55th day of the year in the Gregorian Calendar. There are 310 days remaining, 311 in leap years. By Roman custom February 24 is the day added to a leap year, and the occurrence of February 29 is merely a consequence of this.

Events


- 303 - Galerius, Roman Emperor, publishes his edict that begins the persecution of Christians in his portion of the Empire.
- 1582 - Pope Gregory XIII announces the Gregorian calendar.
- 1711 - The London premiere of Rinaldo by George Friderich Handel, the first Italian opera written for the London stage.
- 1739 - Battle of Karnal: The army of Iranian ruler Nadir Shah defeats the forces of the Mughal emperor of India, Muhammad Shah
- 1803 - The Supreme Court of the United States, in Marbury v. Madison, establishes the principle of judicial review.
- 1804 - London's Drury Lane Theatre burns to the ground, leaving owner Richard Brinsley Sheridan destitute,
- 1826 - The signing of the Treaty of Yandaboo marks the end of the First Burmese War.
- 1831 - The Treaty of Dancing Rabbit Creek, the first removal treaty in accordance with the Indian Removal Act, is proclaimed. The Choctaws in Mississippi cede land east of the river in exchange for payment and land in the West.
- 1839 - William Otis receives a patent for the steam shovel.
- 1848 - King Louis-Philippe of France abdicates the throne.
- 1863 - Arizona is organized as a United States territory.
- 1868 - The first parade to have floats is staged at Mardi Gras in New Orleans, Louisiana.
- 1868 - Andrew Johnson becomes the first President of the United States to be impeached by the United States House of Representatives. He is later acquitted.
- 1881 - China and Russia sign the Sino-Russian Ili Treaty
- 1899 - Western Washington University Established.
- 1909 - The Hudson Motor Car Company is founded.
- 1917 - World War I: The U.S. ambassador to the United Kingdom is given the Zimmermann Telegram, in which Germany pledges to ensure the return of New Mexico, Texas, and Arizona to Mexico if that country declares war on the United States.
- 1918 - Estonia is independent from Imperial Russia.
- 1925 - A thermite (magnesium) bomb is used for the first time to break up a 250,000-ton ice jam clogging the St. Lawrence River near Waddington, New York.
- 1938 - A nylon bristle toothbrush becomes the first commercial product (DuPont) to be made with nylon yarn.
- 1942 - Propaganda: The Voice of America begins broadcasting.
- 1945 - Egyptian Premier Ahmed Maher Pasha is killed in Parliament after reading a decree.
- 1946 - Juan Perón is elected president of Argentina.
- 1948 - Cold War: The Communist Party seizes control of Czechoslovakia.
- 1968 - Vietnam War: The Tet Offensive is halted; South Vietnam recaptures Hué.
- 1970 - National Public Radio is founded.
- 1975 - Hard rock band Led Zeppelin release the classic double album Physical Graffiti.
- 1976 - Cuba : national Constitution proclaimed
- 1981 - Buckingham Palace announces the engagement of The Prince of Wales and Lady Diana Spencer.
- 1981 - Jean Harris is convicted of murdering Dr. Herman Tarnower, the author of the bestselling The Complete Scarsdale Medical Diet.
- 1983 - A special commission of the U.S. Congress releases a report that condemns the practice of Japanese internment during World War II.
- 1988 - The Supreme Court of the United States sides with Larry Flynt's Hustler magazine by overturning a lower court decision to award Jerry Falwell $200,000 for defamation.
- 1989 - Ayatollah Ruhollah Khomeini offers a USD $3 million bounty for the death of The Satanic Verses author Salman Rushdie.
- 1989 - United Airlines Flight 811, bound forNew Zealand from Honolulu, Hawaii, rips open during flight, sucking 9 passengers out of the business-class section.
- 1992 - Nirvana singer Kurt Cobain marries Courtney Love.
- 1995 - The Corona reconnaissance satellite program, in existence from 1959 to 1972, is declassified.
- 1996 - The last occurrence of February 24 as a leap day in the European Union and for the Roman Catholic Church.
- 1999 - The State of Arizona executes Karl LaGrand, a German national involved in an armed robbery, in spite of Germany's legal action to attempt to save him.
- 1999 - A China Southern Airlines Tupolev TU-154 airliner crashes on approach to Wenzhou airport in eastern China killing 61.
- 2002 - 2002 Winter Olympic Games in Salt Lake City, Utah ends.

Births


- 1103 - Emperor Toba of Japan (d. 1156)
- 1304 - Ibn Battuta, explorer
- 1463 - Giovanni Pico della Mirandola, Italian humanist (d. 1494)
- 1500 - Charles V, Holy Roman Emperor (d. 1558)
- 1547 - Don John of Austria, military leader (d. 1578)
- 1557 - Mathias, Holy Roman Emperor (d. 1619)
- 1597 - Vincent Voiture, French poet (d. 1648)
- 1619 - Charles Le Brun, French artist (d. 1690)
- 1622 - Johannes Clauberg, German theologian and philosopher (d. 1665)
- 1684 - Matthias Braun, Czech sculptor (d. 1738)
- 1693 - James Quin, English actor (d. 1766)
- 1709 - Jacques de Vaucanson, French inventor (d. 1782)
- 1723 - John Burgoyne, British general (d. 1792)
- 1774 - Prince Adolphus, 1st Duke of Cambridge (d. 1850)
- 1786 - Wilhelm Grimm, German philologist and folklorist (d. 1859)
- 1836 - Winslow Homer, American artist (d. 1910)
- 1842 - Arrigo Boito, Italian composer (d. 1918)
- 1846 - Luigi Denza, Italian composer (d. 1922)
- 1848 - Andrew Inglis Clark, Tasmanian politician (d. 1907)
- 1852 - George Moore, English writer (d. 1933)
- 1874 - Honus Wagner, baseball player (d. 1955)
- 1877 - Ettie Rout, New Zealand activist (b. 1