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Seven-day week

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This is an old revision of this page, as edited by Sven.ostring (talk | contribs) at 09:24, 23 August 2010 (Correction of the comments about the origin of the seven-day week being a quarter of a lunation.). The present address (URL) is a permanent link to this revision, which may differ significantly from the current revision.

For more information on other weeks, see Week. For more information each day of the week, see Week-day names.
See also: Planetary hours

The seven-day week is used by the majority of the world and is the international standard as specified in ISO 8601.

Origins

The origins of seven-day week can be more specifically identified with the religious significance of the number seven, as opposed to being directly matched with any astronomical cycle. While there have been claims that it was originally derived from a quarter of a lunation, the seven-day week is actually only 23.7% of a lunation. It is more historically accurate to observe that religious significance was attributed to the seven-day week cycle by ancient cultures, specifically the Jewish and Babylonian cultures. The Jews observed a repeated cycle of contiguous seven-day weeks, while in comparison, the Babylonians adjusted the length of the final week in their month so that their monthly calendar would always commence on the new moon.

Ancient Near East

The Babylonian Imago Mundi, dated to the 6th century BC (Neo-Babylonian Empire).[1] The map shows Babylon on the Euphrates, surrounded by a circular landmass showing Assyria, Armenia and several cities, in turn surrounded by a "bitter river" (Oceanus), with seven islands arranged around it so as to form a seven-pointed star.
Further information: Babylonian calendar

Counting from the new moon, the Babylonians celebrated the 7th, 14th, 21st, and 28th as "holy-days", also called "evil days" (meaning "unsuitable" for prohibited activities). On these days officials were prohibited from various activities and common men were forbidden to "make a wish", and at least the 28th was known as a "rest-day". On each of them, offerings were made to a different god and goddess. Tablets from the sixth-century B.C. reigns of Cyrus the Great and Cambyses indicate these dates were sometimes approximate. The lunation of 29 or 30 days basically contained three seven-day weeks, and a final week of nine or ten days inclusive, breaking the continuous seven-day cycle. The Babylonians additionally celebrated the 19th as a special "evil day", the "day of anger", because it was roughly the 49th day of the (preceding) month, completing a "week of weeks", also with sacrifices and prohibitions. Further, reconstruction of a broken tablet seems to define the rarely attested Sapattum or Sabattum as the 15th day of the lunation: this word is cognate with Hebrew Shabbat, but is monthly rather than weekly; it is regarded as a form of Sumerian sa-bat ("mid-rest"), attested in Akkadian as um nuh libbi ("day of mid-repose").[2]

A seven-day week is mentioned in the Creation story contained in the Book of Genesis, in the Hebrew Bible, where God is said to have created the heavens and the earth in six days and rested on the seventh (Genesis 1:1–2:3). Also, in the Book of Exodus, the fourth of the ten commandments is to rest on the seventh day, the Sabbath, which can be seen as implicating a seven-day week social institution (Exodus 20:8–11).

Classical Antiquity

Early evidence of continuous use of a seven-day week appears with the Jews during the Babylonian Captivity in the 6th century BCE.[3], after the destruction of the Temple of Solomon.

The ancient Romans traditionally used the eight-day nundinal cycle, but after the adoption of the Julian calendar, in the time of Augustus, the seven-day week came into use. For a while, the week and the nundinal cycle coexisted, but by the time the week was officially adopted by Constantine in AD 321[4] the nundinal cycle had fallen out of use.

The association of the days of the week with the seven planets visible with the naked eye dates to the Roman era (2nd century).

Christian Europe

The seven-day weekly cycle is reputed[citation needed] to have remained unbroken in Europe for almost two millennia, despite changes to the Alexandrian, Julian, and Gregorian calendars.

The date of Easter Sunday can be traced back through numerous computistic tables to an Ethiopic copy of an early Alexandrian table beginning with the Easter of 311 CE[5]

Adoption after other systems

China

The earliest known reference in Chinese writings to a seven-day week is attributed to Fan Ning, who lived in the late 4th century in the Jin Dynasty, while diffusions from the Manichaeans are documented with the writings of the Chinese Buddhist monk Yi Jing and the Ceylonese or Central Asian Buddhist monk Bu Kong of the 7th century (Tang Dynasty).

France

Main article: French republican calendar

France discontinued the seven-day week for a ten-day week with the introduction of the republican calendar in 1793. The Concordat of 1801, which re-established the Roman Catholic Church in France, also restored the seven-day week, beginning with Easter Sunday, 18 April 1802.

Japan

The Chinese transliteration of the planetary system was soon brought to Japan by the Japanese monk Kobo Daishi. Surviving diaries of the Japanese statesman Fujiwara Michinaga show the seven-day system in use in Heian Period Japan as early as 1007. In Japan, the seven-day system was kept in use for astrological purposes until its promotion to a full-fledged Western-style calendrical basis during the Meiji era.

Hindu

The seven-day week may have been in use during the Vedic Period, although according to Pandurang Vaman Kane author of History of Dharmasastra "this is not conclusive".

The Pañcasiddhāntikā mentions 'Monday'. The Garga dated 1st Century BCE, refers to the seven-day week, Sunday to Saturday.

He concludes "the above references furnish a terminus ad quem (viz. 1st century BCE–1st century CE) The terminus a quo cannot be stated with certainty".[6][7]

Soviet Union

Main article: Soviet calendar

In 1929 USSR discontinued the seven-day week for a five-day week, then a six-day week. While the days were still named according to the seven-day week, the work schedules were rotated in five- and six-day periods. The seven-day week was reintroduced on 27 June 1940.

Week numbering

Weeks in a Gregorian calendar year can be numbered for each year. This style of numbering is commonly used (for example, by schools and businesses) in some European and Asian countries, but rare elsewhere.

ISO 8601 includes the ISO week date system, a numbering system for weeks – each week begins on a Monday and is associated with the year that contains that week's Thursday (so that if a year starts in a long weekend Friday–Sunday, week number one of the year will start after that). For example, week 1 of 2004 (2004W01) ran from Monday 29 December 2003 to Sunday, 4 January 2004, because its Thursday was 1 January 2004, whereas week 1 of 2005 (2005W01) ran from Monday 3 January 2005 to Sunday 9 January 2005, because its Thursday was 6 January 2005 and so the first Thursday of 2005. The highest week number in a year is either 52 or 53 (it was 53 for year 2004). Schematically, this ISO convention translates as follows:

Dates in January Effect
M T W T F S S Week number Week assigned to
1 2 3 4 5 6 7 1 New year
1 2 3 4 5 6 1 New year
1 2 3 4 5 1 New year
1 2 3 4 1 New year
1 2 3 52 or 53 Previous year
1 2 52 or 53 Previous year
1 52 or 53 Previous year

In some countries, though, the numbering system is different from the ISO standard. At least six numberings are in use:[8][9]

First day of week First week of year contains Weeks assigned twice Used by/in
Monday 4 January 1st Thursday 4–7 days of year no Most of Europe and countries adhering to ISO 8601
Saturday 1 January 1st Friday 1–7 days of year yes Much of the Middle East
Sunday 1 January 1st Saturday 1–7 days of year yes Canada, USA

Facts and figures

  • 1 week = 7 days = 168 hours = 10,080 minutes = 604,800 seconds (except at daylight saving time transitions or leap seconds)
  • 1 Gregorian calendar year = 52 weeks + 1 day (2 days in a leap year)
  • 1 week = 23.01% of an average month

In a Gregorian mean year there are approximately 365.2425 days, and thus approximately 52.1775 weeks (unlike the Julian year of 365.25 days or 52+5⁄28 weeks, which cannot be represented by a finite decimal expansion). There are exactly 20871 weeks in 400 Gregorian years, so 10 April 1611 was a Sunday just like 10 April 2011.

A system of Dominical letters has been used to determine the day of week in the Gregorian or the Julian calendar.

See also

References

  1. ^ Siebold, Jim. "Slide 103". Retrieved 2009-01-21.
  2. ^ Pinches, T.G. (2003). "Sabbath (Babylonian)". In Hastings, James (ed.). Encyclopedia of Religion and Ethics. Vol. 20. Selbie, John A., contrib. Kessinger Publishing. pp. 889–891. ISBN 9780766136984. Retrieved 2009-03-17.
  3. ^ Senn, Frank C. (1997). Christian Liturgy: Catholic and Evangelical. Fortress Press. ISBN 0800627261, 9780800627263. {{cite book}}: Check |isbn= value: invalid character (help)
  4. ^ Zerubavel, Eviatar (1989). The Seven Day Circle: The History and Meaning of the Week. University of Chicago Press. p. 45. ISBN 0226981657, 9780226981659. {{cite book}}: Check |isbn= value: invalid character (help)
  5. ^ Neugebauer, Otto (1979). Ethiopic astronomy and computus. Verl. d. Österr. Akad. d. Wiss. ISBN 3700102895, 9783700102892. {{cite book}}: Check |isbn= value: invalid character (help)
  6. ^ Shashi, Shyam Singh (2000). Encyclopaedia Indica India, Pakistan, Bangladesh Vol. 76 Major dynasties of ancient Orissa: India, Pakistan, Bangladesh. Anmol Publications PVT. LTD. pp. 114–115. ISBN 8170418593, 9788170418597. {{cite book}}: Check |isbn= value: invalid character (help)
  7. ^ Kane, Dr. Pandurang Vaman (1930–1962). History of Dharmasastra.{{cite book}}: CS1 maint: date format (link)
  8. ^ Weeknumber sorted by definition
  9. ^ Calendar Weeks
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