The week today is a common time unit of seven days in almost all cultures . In most countries, however, it is neither a legal unit nor a physical unit of measurement in the sense of a system of units . Nevertheless, according to the German Civil Code (e.g. Paragraph 2) and the Swiss Code of Obligations (Art. 77 Paragraph 1 Item 2 OR), deadlines can be specified in weeks, whereby in Germany the week is usually Monday 0: 00:00 to Sunday 24:00 is defined ( Working Hours Act ).
According to the recommendation made by the International Organization for Standardization (ISO) in 1975 , the days of the week have had the following sequence since January 1976: Monday , Tuesday , Wednesday , Thursday , Friday , Saturday / Saturday and Sunday .
According to Jewish and Christian tradition, the week starts on Sunday. The same is done today in the USA, Israel, Arab countries, Japan and China. The German term "Wednesday" also refers to a week beginning on Sunday and not on Monday. However, the calendars of most European countries mark Monday as the first day of the week, as provided for in the ISO 8601 standard . According to old Persian tradition, the week begins on Saturday.
In Germany, the DIN standard DIN 1355 was valid from 1943 , which was changed in 1975 with effect from 1976, then merged into EN 28601 in 1992 and was replaced by the currently valid ISO 8601 in September 2006 .
The word week is related to the words turnout and change .
The combination of seven days into a unit of one week can be explained with the length of a month ( moon ), which comprises a little more than 28 days. The four moon phases ( new light after new moon, waxing crescent moon, full moon , waning crescent moon, new moon ) then allow an obvious division of the 28 days of the month into four weeks of seven days each. An old naming and order of the days of the week comes from Babylonia and Egypt , where already in the Old Kingdom (3rd millennium BC) the month was divided into the four phases of the moon and related religious sacrifices were made. A deity was assigned to each day, and a day of the week was assigned to each of the movable celestial objects known at the time (sun, moon, Mars, Mercury, Jupiter, Venus and Saturn).
In Semitic languages , the word for week ( Hebrew שבוע schawua , Arabic أسبوع) on the same root as the name for the number seven, also sa-ba-tu in the Babylonian language was the name for the seventh day after the new light.
In the oldest written Torah - and thus also the Bible - traditions ( 5th century BC ) a seven-day week is explicitly mentioned, whereby the first six days are designated with numbers, while the seventh day is the general "day of rest" is highlighted, see Gen 2.2 EU . It has not yet been clarified whether the tradition of the Torah was linked to the seven-day week from the beginning or whether two originally separate traditions were only linked later. The name Sabbath for the “day of rest”, on the other hand, is attested much later. The name derivation is also not clear. Modern research discusses on the one hand the origin of the Hebrew term šbt ("stop, let off work, celebrate") and on the other hand the Babylonian equivalent šapattu (moon festival). According to Christian tradition, most Christians celebrate the first day of the week, Sunday (the day of the sun; day on which sacrifices were made to the sun god) as the commemoration day of the resurrection of Jesus of Nazareth. The commandment to keep the Sabbath day holy is reinterpreted in this sense (“You are to keep the holiday holy”).
When and by whom the counting of the days of the week, which is still common today, was first established cannot be traced.
Today's seven-day week replaced the ancient Roman Nundinum under oriental influence , possibly significantly through the calendar reform of Gaius Iulius Caesar in 45 BC. In legal terms, however, the 7-day week can only be made legally binding with Emperor Constantine from 321 AD in the legislation on freedom of work and court days on Sundays.
There is no evidence that the sequence of the seven days of the week has ever been interrupted since its inception, not even by the calendar reform of the Gregorian calendar . This makes it the most regular part of the Julian and Gregorian calendars.
The calendar year comprises at least 52 weeks. a. in business life are numbered consecutively as calendar weeks (KW), whereby there are different definitions for the week numbering. Depending on the rule applied, the first week of a year can be set differently:
- In German-speaking countries, in accordance with ISO , DIN , ÖNORM and SN standards : the week that includes the first Thursday of the year ( ISO 8601 , formerly DIN 1355-1 ). Since ISO 8601 defines Monday as the first day of the week, this is the first week of which more days (at least four) fall in the new year than in the old year. The following definitions are equivalent to this:
- that week that includes January 4th
- the week that includes January 1st if this is a Monday, Tuesday, Wednesday or Thursday, otherwise the following week
- In the USA : the week that falls on January 1st
- Rare: the first full week of the year
Counting according to ISO 8601
- Calendar weeks have 7 days, start on a Monday and are numbered consecutively throughout the year.
- Calendar week 1 of a year is the one that contains the first Thursday .
Further characteristics of this counting method are:
- Each year has either 52 or 53 calendar weeks.
- A year has 53 calendar weeks if it begins or ends with a Thursday:
- December 29th, 30th and 31st can belong to calendar week 1 of the following year.
- January 1st, 2nd and 3rd can still belong to the last calendar week of the previous year.
- January 4th is always in week 1.
In Germany, the leading German institute for standardization with the DIN 1355-1 an appropriate counting with Monday as the first day of the week in Germany on January 1, 1976th In the previous version DIN 1355 from 1943, the week started on Sunday. In calendars for German-speaking countries, the calendar week is always counted according to ISO 8601, even if Sunday is sometimes shown as the beginning of the week.
In March 1975, DIN recommended for the Federal Republic of Germany to assign the ordinal number 1 to the weekday Monday (DIN 1355); this has led to the custom of viewing Monday as the first day of the week and thus the beginning of the week. Before that, there had been a regulation in German standards since January 1943: "A week begins on Sunday at 0:00 and ends on the following Saturday at 24:00". In the GDR , this change came into effect in 1969/1970. In 1978 the UN decided that Monday should be considered the first day of the week internationally.
- Calendar week KW 52, 2003: "2003-W52" - Monday, December 22, 2003 to Sunday, December 28, 2003
- Calendar week 1, 2004: "2004-W01" - Monday, December 29, 2003 to Sunday, January 4, 2004
Calculation in the USA and many other countries
In large parts of the world (e.g. North America, Australia) the Judeo-Christian tradition has been preserved of counting Sunday as the first day of the week. In the USA and countries that also use the scheme valid there, the following rules apply:
- A new calendar week begins every Sunday.
- The 1st calendar week always begins on January 1st - regardless of the day of the week.
From this, some properties can be derived:
- The first and last calendar weeks of a year do not have to be complete; that is, they can contain fewer than seven days
- Every year that is not a leap year or whose December 31st is not a Sunday has 53 calendar weeks.
- If December 31st of a leap year is a Sunday, then this Sunday is the only day in the 54th calendar week (this case occurs relatively rarely; every seven leap years within a century: most recently in 1944, 1972 and 2000, the next Times 2028 and 2056).
A modified form of this calculation scheme, which is neither standardized nor common in the USA, uses, similar to the DIN scheme, only full weeks and defines the first calendar week that contains January 1st. In this case, the days after the last Saturday in December can already belong to the first calendar week of the following year, while a 54th calendar week never occurs.
In US business life and in public communication there, calendar weeks in the form of consecutive numbers as above are rarely used. Instead, a week is usually denoted by its Monday, e.g. B. week of June 20 .
Further calculation variants
In Portuguese , the days of the week are counted except Saturday and Sunday, with Monday being the second and Friday being the sixth. This means that Saturday ( Sabbath ) is counted as the seventh day of the week. It is the same in Japan (see Japanese calendar, days of the week ). In China , the days of the week are counted from Monday (1) to Saturday (6) and named accordingly, but Sunday is not day seven, but "Heaven's Day".
Other systems for short periods of time
The seven-day week system has established itself today in all large cultures, such as arithmetic with ten digits. In earlier cultures there were other systems of counting the day:
- In ancient Egypt , the calendar was divided into 36 weeks of 10 days each, known as decades or deans .
- 10-day weeks were also used in the Attic calendar . In months with 29 days, however, one day was left out in the third decade.
- In the Roman Empire there was an eight-day week, the so-called Nundinae due to the earlier inclusive counting . In addition, a month three Fixtage were Kalends , Nones and Ides related. In the year 321 AD this system was replaced by the Christian week with Sunday as the official day of rest.
- The Aztecs reckoned with a five-day and a 13-day phase (s) . The normal Aztec calendar was based on the solar year and was xihuitl (at the Mayan haab ). It comprised 18 months of 20 days each plus five extra days that are said to have been unfortunate. Each month had four weeks of five days each. The last day of the week was public market day ( tianquiztli ) and at the same time a day of celebration and rest. There were a total of 288 working days and 72 tianquiztli per year. You shouldn't work on the five unlucky days. That made a total of 365 days. But since the year is about six hours longer, the calendar shifted compared to the actual solar year. According to the overwhelming majority, this shift was not compensated for by leap days or in any other way.
- There was a second sacred calendar with 260 days, the so-called tonalpohualli , which was used for prophecies. The 260 days were divided into 20 weeks of 13 days each. Each day was assigned to a god (or a goddess). People's fate depended on whether their birthday was assigned good or bad qualities. For example, "Seven Rain" was a good day, "Two Rabbits" a bad day.
- Even according to the French revolutionary calendar introduced in 1792, there was a ten-day week. There were three such ten-day weeks per month, so each month had 30 days. Five extra days were added at the end of the year. On January 1st, 1806, Napoleon abolished this new era.
- The Soviet calendar of the October Revolution from 1929 to 1940 also had a five-day week, albeit with six-week months.
- A five-day week is also used in the Discordian calendar .
- In many regions of West and Central Africa (e.g. in the Kingdom of the Congo ) a calendar based on the four-day week applied . The following applied: 1 week comprised 4 days, the month comprised 7 weeks and the year comprised 13 months plus 1 day. With the adoption of Christianity, the Christian calendar increasingly supplanted the use of this calendar.
- In Balinese Hinduism , several counting systems are still ritually used today ( pawukon ). Combining these systems results in 55 (= 1 + 2 + 3 + 4 + 5 + 6 + 7 + 8 + 9 + 10) different days. In practice, the combination of:
- Triwara = three days
- Pancawara = five days
- Saptawara = seven-day week
- The Triwara is the usual cycle of market days in Bali: every third day is market day in a village.
- Alois Walde: Latin etymological dictionary , 3rd edition., Obtained from Johann Baptist Hofmann, Heidelberg 1938 (= Indo-European Library, First Department, II. Row, 1), reprints ibid. 1954 and 1972, II, p. 782.
- Karl-Heinrich Bieritz : The church year . In: Hans-Christoph Schmidt-Lauber , Michael Meyer-Blanck, Karl-Heinrich Bieritz: Handbook of the liturgy - liturgical science in theology and practice of the church . Vandenhoeck & Ruprecht, Göttingen 2003, ISBN 3-525-57210-7 , p. 359.
- Cf. Alexandra von Lieven : Plan of the course of the stars - the so-called groove book . The Carsten Niebuhr Institute of Ancient Eastern Studies (among others), Copenhagen 2007, ISBN 978-87-635-0406-5 , p. 147.
- Codex Theodosianus 2,8,1 ( Memento of the original from November 20, 2012 in the Internet Archive ) Info: The archive link has been inserted automatically and has not yet been checked. Please check the original and archive link according to the instructions and then remove this notice.
- z. E.g .: The View ( Memento of the original from June 28, 2011 in the Internet Archive ) Info: The archive link was inserted automatically and has not yet been checked. Please check the original and archive link according to the instructions and then remove this notice. .
- Jan Vansina: The Kingdoms of the Savanna. 1966, p. 24.