Week

Italian Bracelet of the centuryXIX which represents the days of the week with the associated Roman gods:
Diana-Luna, Mars, Mercury, Jupiter, Venus, Saturn and Apollo-Sol

Roman Mosaic of the Domus of the Planetarium, Italica

It is known as week (from the late Latin septimāna, and this from the Latin septem, 'seven') or rarely as hebdómada (from Latin hebdomăda, and this from Greek ἑβδομάς, -άδος hebdomás, -ádos) to the cycle made up of seven days in a row; that is to say, the period of 7 consecutive calendar days, which according to the ISO 8601 standard adopted by most of the countries of the world, begins on Monday and ends on Sunday.

Like the division of the day into 24 hours, the seven-day cycle comes from Babylonian astronomy. Each hour of the day was assigned a classical planet, in a cycle that began with the furthest away: Saturn, Jupiter, Mars, Sun, Venus, Mercury, and Moon. In Spanish the names derive from this cycle, except the sixth and seventh that do from the Christian tradition, which results in the current names of the days of the week: Monday, Tuesday, Wednesday, Thursday, Friday, Saturday and Sunday.

However, in many regions these references are totally or partially absent and the days of the week are numbered. There are countries that consider Sunday the first day of the week, in accordance with the Christian liturgical week, or that make it start on Saturday, in some Muslim countries.

The week is the standard time period used for cycles of work and rest days in most parts of the world.

History

The so-called 7 classic planets, located in spheres outside the earth and within the sphere of the firmament

Origin

It is assumed that in the early days of humanity, when humans discovered the solar cycle, they realized that the elapsed time and age of a person could be measured by the number of steps from winter to spring that he had lived When the annual cycle became more known, it could be divided into 4 quarterly seasons (more or less conventional, since the seasons never lasted the same amount of time or were exactly the same).

At some point (before or after the above discovery) the lunar phase cycle was discovered. The Moon goes through four moments that are easy to discriminate:

• Full moon (completely illuminated).
• dwindling moon (lit in one half).
• New moon (completely darkened).
• growing moon (lit in its other half).

There is approximately a seven-day week between two lunar phases.

Counting from the new moon, the Babylonians celebrated a cycle of seven days dedicated to the seven "planets" or deities. In each of them, attention was paid (and offerings were made, to also enlighten those less able to think in the abstract) to a different aspect of reality, what the illusion called gods: Marduk and Ishtar on the 7th, Ninlil and Nergal on the 14th, Sin and Shamash on the 21st, and Enki and Mah on the 28th. The tablets of the reigns of the century VI a. C. of Cyrus the Great and Cambyses II indicate that these dates were sometimes approximate. The start of the lunation was sometimes approximate; the end of the cycle, contained between one and three days of rest, and sometimes up to a last week of eight or nine days inclusive, breaking the continuous cycle of seven days. ^{[citation required]}

In the Christian religion, as in Judaism, the idea is held that the weekly cycle of seven days is due to the fact that it took God seven days to finish the creation of the world. In the weekly cycle described by the Hebrew scriptures, Sunday is considered as the first day of the weekly cycle and Shabbat (in Hebrew) or Saturday as the seventh and last day of the week as described in the book of Genesis "the heavens and the earth and all the host of them were finished, and on the seventh day God finished the work that he had done" (Genesis 1:1 - 2:1-3).

Classic planets

Sculptures by Diana, Mercury, Venus, Apollo, Mars, Jupiter and Saturn at the Fronteira Palace

The Latin names of the gods related to the mobile stars of the firmament are the translation of the Greek names, which in turn are adaptations of the Babylonian names, which go back to the Sumerians.

However, successive interpretations slightly distorted the original relationships. Nergal, for example, was the god of war but also of pestilence and especially of hell, which overlapped attributes of the Greek Ares and Hades. Also while Cronus is the father of Zeus, Ninurta is the son of Enlil. The Babylonians replaced the Sumerian national gods Enlil and Enki with Babylon's patron god Marduk and his son, Nabu, despite Marduk's considered the son of Enki (Ea in Babylon). Ninurta, a dark god inherited from the Babylonians, may have been identified with Saturn, the slower-moving planet, because, in at least one story, he appears as a tortoise.

Planetary Hours

The best-known hypothesis about the origin of the order of the planets is the following: if the planets are arranged according to the erroneous knowledge ―from a geocentric astronomy― that the ancients had of their respective distances from Earth ―in reality of How long did it take to make a complete cycle in relation to the background of stars―, the order (from far to near, or from slower to faster) would be:

• Saturn (),
• Jupiter (Jupiter)),
• Mars (),
• Sun (),
• Venus (),
• Mercury (),
• Moon).

Time:	1	2	3	4	5	6	7	8	9	10	11	12	13	14	15	16	17	18	19	20	21	22	23	24	Astro → Day
Day 1																									Saturn → Saturday
Day 2																									Sun → Sunday
Day 3																									Moon → Monday
Day 4																									Mars → Tuesday
Day 5																									Mercury → Wednesday
Day 6																									Jupiter → Thursday
Day 7																									Venus → Friday

Some Mediterranean peoples thought that each hour of the day was ruled by the Sun, the Moon, or one of the five planets known at the time. Which were gods that revolved eternally around the Earth. The sequence in which they ruled corresponded to the reverse order of their distances from Earth.

According to Vetio Valente, who lived in the II century AD. C. and is the best-known authority on astrology in the ancient world, the first hour of the day began at sunset, which was traditional among the Greeks and Babylonians. He also says that the day and night halves of the day were presided over by the stars that correspond to the first hour of each half. This is confirmed by a Pompeian graffiti that names February 6, 1960 as a Sunday, when today it would be said that it was Wednesday. Apparently, the count of the days of the week after the first daylight hour constituted an alternate week to the ordinary, as is clear from the Easter letters of Bishop Athanasius, and in a surviving table of Easter dates for the years 311-369. in an Ethiopian copy.

Continuity of the seven-day cycle

In Europe there is a tradition of reform since pre-Christian times, proof of this are the solar and lunisolar calendars such as the Hellenic calendar, the Roman calendar, the Julian calendar and even the current Gregorian calendar.

Names of the days

The origin of these names is in the observation of the sky by the ancients. During the year, the vast majority of the visible stars did not change position with respect to each other. However, those human beings observed with the naked eye seven celestial bodies that did vary in position: the Sun, the Moon, and the five planets that can be seen with the naked eye: Mars, Mercury, Jupiter, Venus and Saturn.

While Eastern Mediterranean languages reflect the numbering of the days of the week, Western European languages (except Portuguese) reflect the names of the moving stars in the firmament: Moon, Mars, Mercury, Jupiter, Venus, Saturn, Sun. These seven celestial bodies gave their names to the days of the week: Monday, Tuesday, Wednesday, Thursday, Friday. In Spanish, sábado comes from the Hebrew word shabbat (day of rest), and domingo from the Latin word domínica (day of the Lord). However, in some languages (like English, for example), the original names of these two days are maintained: saturday (day of Saturn) and sunday (day of Sun); and in other languages the Greco-Roman gods are substituted with more or less corresponding Germanic gods. Thus, the Germanic god of war Tiw (tuesday) replaces the Greco-Roman martial Mars, the main Germanic god Woden (wednesday) for the secondary god Mercury, the important warrior god Thor (thursday) to the all-important Jupiter, the fertility goddess Freya or Frigg (friday) to the love goddess Venus.

In Hebrew they are simply numbered (first day, second day, third day, etc.) counting from Sunday, except for the seventh and last, which is called shabbat.

In Arabic they are also numbered except for the sixth al-Jum'ah and the seventh asSabt.

In modern Greek they are also numbered except for the first kyriakí (Lord's day), the sixth paraskeví (day of preparation) and the seventh sávato,

In Portuguese the days from Monday to Friday are called segunda-feira, terça-feira, quarta-feira, quinta -feira, and sexta-feira, and the remaining two are called as in Spanish, sábado and domingo.

Numbering the days

Start of the week

Icon that marks the day of the week and the month.

In 1988 the ISO 8601 standard was signed, which is the international convention that indicates the order of the days of the week. This norm establishes that the week begins on Monday and ends on Sunday, being the norm that is followed in the vast majority of countries in the world. However, in liturgical calendars and in some countries, the week begins on Sunday.

In 2012, in the UK, most planners and calendars use Monday as the start of the week; however some use Sunday.

In Brazil and Portugal, although the week starts on Monday since the 1990s, the names of the days suggest that traditionally the week started on Sunday: Monday is called segunda-feira ('second feria'), Tuesday terça-feira ('third fair'), etc. In any case, Saturday and Sunday are identified as the weekend.

In Judaism, the beginning and end of the week is based on the writing "...for in six days God made the heavens and the earth, and on the seventh day he rested" (Exodus 31-16), said writing is attached to the belief that the days begin with sunset and end with sunset the following day; “...and there was evening and there was dawn of a day" (Genesis 1-5). For this reason, in Israel the week begins on Saturday after sundown (although most people start work on Sunday, many businesses start work again from Saturday night).

Weekend

Cultures with a strong European heritage—and some others—take Friday, Saturday, and Sunday as the weekend. Several Muslim countries take Saturday and Sunday as their weekend (all include Friday). In 1976, when Algeria gained independence from the French Empire, to differentiate itself from its conquerors it changed the weekend from Saturday-Sunday to Thursday-Friday (respecting the Muslim holy day of Friday). In mid-August 2009, Algeria ―in order to increase trade with other countries― again changed the weekend from Thursday-Friday to Friday-Saturday.

Alternative periods

Page of December 12, 1937, sixth day of the six-day week of the Soviet revolutionary calendar: "The Day of Elections to the Supreme Soviet of the Soviet Union".

In some revolutionary calendars the duration of the week changes, and the name of the week also changes, since etymologically the term «week» comes from «seven» (septem in Latin).

French decade

The French Revolution instituted a ten-day week, abolished by Napoleon.

In the French republican calendar, the year is divided into 36 decades (periods of 10 days) and 5 or 6 additional days. Even today, decade means a period of 10 days, while to refer to a decade or a period of 10 years, one must use decennie (decade).

Soviet

The Russian revolution changed to a six-day week, five working days and one off, which lasted until 1940.

In the Soviet revolutionary calendar, the seven-day week was replaced by a five-day week in order to suppress the religious connotations of Saturday and Sunday. However, this initiative - which was gradually introduced in 1929 - only lasted two years (until September 1, 1931). In the remaining nine years in which this revolutionary calendar was used, a six-day week with a fixed day of rest was used, which fell on the 6th, 12th, 18th, 24th and 30th of each month. The last day of months with 31 days was considered an extra business day outside of the normal six-day cycle. On June 26, 1940, the seven-day week was restored.