Editing Week (section)

==History==
[[File:CLM 14456 71r detail.jpg|thumb|upright=1.75|Circular diagrams showing the division of the day and of the week, from a [[Carolingian Renaissance|Carolingian]] ms. ([[Codex latinus monacensis|Clm]] 14456 fol. 71r) of [[St. Emmeram Abbey]]. The week is divided into seven days, and each day into 24 hours, 96 {{lang|la|puncta}} (quarter-hours), 240 {{lang|la|minuta}} (tenths of an hour) and 960 {{lang|la|cat=no|[[moment (unit)|momenta]]}} (40th parts of an hour).]]

===Ancient Near East===
The earliest evidence of an astrological significance of a seven-day period is  decree of king [[Sargon of Akkad]] around 2300 BCE. Akkadians venerated the number seven, and the key celestial bodies visible to the naked eye numbered seven (the Sun, the Moon and the five closest planets).<ref>{{cite web |title=How we divide time |url=https://www.rmg.co.uk/stories/topics/why-12-months-year-seven-days-week-or-60-minutes-hour |website=[[Royal Museums Greenwich]] |access-date=12 September 2024}}</ref>

[[Gudea]], the priest-king of [[Lagash]] in [[Sumer]] during the [[Gutian dynasty of Sumer|Gutian dynasty]] (about 2100 BCE), built a seven-room temple, which he dedicated with a seven-day festival. In the flood story of the [[Mesopotamia|Assyro-Babylonian]] [[Epic of Gilgamesh]], the storm lasts for seven days, the dove is sent out after seven days (similarly to Genesis), and the [[Noah]]-like character of [[Utnapishtim]] leaves the ark seven days after it reaches the firm ground.{{efn|1=Copeland (1939) states as the date for Gudea "as early as 2600 BCE";<ref>{{cite journal |last=Copeland |first=Leland S. |title=Sources of the Seven-Day Week |journal=Popular Astronomy |date=1939 |volume=47 |issue=4 |page=176 |bibcode=1939PA.....47..175C}}</ref> the modern estimate according to the [[short chronology]] places Gudea in the 22nd century BCE. By contrast, [[Anthony R. Michaelis]] claims that "the first great empire builder, King Sargon I of Akkad ([ruled] 2335 to 2279 BCE [viz., middle chronology]), decreed a seven-day week in his empire. He lived for 56 years, established the first Semitic Dynasty, and defeated the Sumerian City-States. Thus the Akkadian language spread, it was adopted by the Babylonians, and the seven-day week was similarly inherited from him."<ref>{{cite journal |title=The Enigmatic Seven |url=http://garfield.library.upenn.edu/michaelis/title310.pdf |journal=Interdisciplinary Science Reviews |volume=7 |page=373 |last=Michaelis |first=Anthony R.|year=1982 |issue=1 |doi=10.1179/030801882789801278 |bibcode=1982ISRv....7....1M }}</ref> The number seven is significant in Sumerian mythology.<ref>{{cite news |title=The power of seven |date=20 December 2001 |url=http://www.economist.com/node/895542?fsrc=scn/fb/wl/ar/thepowerofseven |newspaper=[[The Economist]]}}</ref><!--surely(!) we can come up with a better source for whatever we want to say with this.-->}}

Counting from the [[new moon]], the Babylonians celebrated the 7th, 14th, 21st and 28th of the approximately 29- or 30-day lunar month as "holy days", also called "evil days" (meaning inauspicious for certain 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".<ref name=ere/>
On each of them, offerings were made to a different god and goddess. Though similar, the later practice of associating days of the week with deities or planets is not due to the Babylonians.<ref>{{cite journal |last1=Emil Schürer |title=Die siebentägige Woche im Gebrauche der christlichen Kirchen der ersten. Jahrhunderte |journal=[[Zeitschrift für die neutestamentliche Wissenschaft]] |date=1905 |pages=1–66 |url=https://dlibra.bibliotekaelblaska.pl/Content/56671/01.pdf |author1-link=Emil Schürer }}</ref>

===Judaism===
A continuous seven-day cycle that runs throughout history without reference to the phases of the moon was first practiced in [[Judaism]], dated to the 6th century BCE at the latest.{{sfnp|Zerubavel|1989|loc=[https://books.google.com/books?id=Cd5ZjRsNj4sC&pg=PA11 p. 11]}}<ref name="Senn 1997"/>

There are several hypotheses concerning the origin of the [[Old Testament|biblical]] seven-day cycle.

[[Friedrich Delitzsch]] and others suggested that the seven-day week being approximately a quarter of a [[lunation]] is the implicit astronomical origin of the seven-day week,<ref name="LSC">{{cite journal
|last=Leland
|first=S. Copeland
|title=Sources of the Seven-Day Week
|journal=Popular Astronomy
|url=http://adsabs.harvard.edu/full/1939PA.....47..175C
|date=April 1939
|volume= XLVII| issue = 4
|page=176 ff
|bibcode=1939PA.....47..175C}}
</ref> and indeed the [[Babylonian calendar]] used [[Intercalation (timekeeping)|intercalary]] days to synchronize the last week of a month with the new moon.<ref>A month consisted of three seven-day weeks and the fourth week of eight or nine days, thus breaking the seven-day cycle every month. Consequently, there is no evidence that the days of the week were given individual names in Babylonian tradition. {{cite book|author=Pinches, T.G.|editor=Hastings, James|others=Selbie, John A., contrib|title=Encyclopedia of Religion and Ethics|volume=20|publisher=Kessinger Publishing|year=2003|pages=889–891|chapter=Sabbath (Babylonian)|url=https://books.google.com/books?id=qVNqXDz4CE8C|isbn=978-0-7661-3698-4 |access-date=17 March 2009}}</ref> According to this theory, the Jewish week was adopted from the Babylonians while removing the moon-dependency.

[[George Aaron Barton]] speculated that the seven-day creation account of Genesis is connected to the Babylonian creation epic, [[Enûma Eliš]], which is recorded on seven tablets.<ref>"Each account is arranged in a series of sevens, the Babylonian in seven tablets, the Hebrew in seven days. Each of them places the creation of man in the sixth division of its series." cited after Albert T. Clay, ''The Origin of Biblical Traditions: Hebrew Legends in Babylonia and Israel'', 1923, [https://books.google.com/books?id=JKBLAwAAQBAJ&pg=PA74 p. 74].</ref>

In a frequently-quoted suggestion going back to the early 20th century,<ref>{{cite book |chapter-url=https://babel.hathitrust.org/cgi/pt?id=mdp.39015027068470;view=1up;seq=197 |chapter=The Babylonian Sabbath |page=181 |url=https://babel.hathitrust.org/cgi/pt?id=mdp.39015027068470;view=1up;seq=9 |title=The American Antiquarian and Oriental Journal |volume= XXX |year=1908 |access-date=21 June 2018}}</ref> the Hebrew ''[[Biblical Sabbath#Etymology|Sabbath]]'' is compared to the Sumerian ''sa-bat'' "mid-rest", a term for the [[full moon]]. The Sumerian term has been reconstructed as rendered ''Sapattu<sup>m</sup>'' or ''Sabattu<sup>m</sup>'' in [[Babylonian language|Babylonian]], possibly present in the lost fifth tablet of the [[Enûma Eliš]], tentatively reconstructed {{according to whom|date=April 2015}} "[Sa]bbath shalt thou then encounter, mid[month]ly".<!-- [[Akkadian language|Akkadian]] ''um nuh libbi'' ("day of mid-repose") what is this, a reconstruction or an extant translation of Enuma Elish?--><ref name="ere">{{cite book|author=Pinches, T.G.|url=https://books.google.com/books?id=qVNqXDz4CE8C|title=Encyclopedia of Religion and Ethics|publisher=Kessinger Publishing|others=Selbie, John A., contrib|year=2003|isbn=978-0-7661-3698-4|editor=Hastings, James|volume=20|pages=889–891|chapter=Sabbath (Babylonian)|access-date=17 March 2009}}
<!--it turns out this ERE article just summarizes a century-old Assyriologist theory, but we don't know whose it is, or how scholars have judged it--></ref>

However, [[Niels-Erik Andreasen]], [[Jeffrey H. Tigay]], and others claim that the [[Biblical Sabbath]] is mentioned as a day of rest in some of the earliest layers of the [[Pentateuch]] dated to the 9th century BCE at the latest, centuries before the [[Babylonian exile of Judah]]. They also find the resemblance between the Biblical Sabbath and the Babylonian system to be weak. Therefore, they suggest that the seven-day week may reflect an independent [[Israelites|Israelite]] tradition.<ref>{{cite book |url=https://books.google.com/books?id=kE0YAAAAIAAJ |title=The Old Testament Sabbath: A Tradition-historical Investigation |last=Andreasen |first=Niels-Erik A. |date=1972 |publisher=Society of Biblical Literature |isbn=9780891306832 |language=en}}</ref><ref>{{cite journal |last=Shafer |first=Byron E. |date=1974 |title=Reviewed Work: ''The Old Testament Sabbath: A Tradition-Historical Investigation'' by Niels-Erik A. Andreasen |jstor=3263102 |journal=Journal of Biblical Literature |volume=93 |issue=2 |pages=300–301 |doi=10.2307/3263102}}</ref><ref name=":1">{{cite journal |last=Tigay |first=Jeffery H. |date=1998 |title=Shavua |journal=Mo'adei Yisra'el: Time and Holy Days in the Biblical and Second Commonwealth Periods (Heb.), ed. Jacob S. Licht|pages=22–23 }}</ref><ref>{{cite journal |jstor=23506909 |title=New Moons and Sabbaths: A Case-Study in the Contrastive Approach |journal=Hebrew Union College Annual |volume=48 |year=1977 |pages=1–18 |last=Hallo |first=William W.}}</ref> Tigay writes:

<blockquote>It is clear that among neighboring nations that were in position to have an influence over Israel – and in fact which did influence it in various matters – there is no precise parallel to the Israelite Sabbatical week. This leads to the conclusion that the Sabbatical week, which is as unique to Israel as the Sabbath from which it flows, is an independent Israelite creation.<ref name=":1"/><ref>{{cite journal |last=Friedman |first=Allen |date=Sep 2008 |title=Unnatural Time: Its History and Theological Significance |jstor=40914729 |journal=The Torah U-Madda Journal |volume=15 |pages=104–105 |postscript=, Tigay's citation. }}</ref></blockquote>

The seven-day week seems to have been adopted, at different stages, by the [[Persian Empire]], in [[Hellenistic astrology]], and (via [[Hellenistic period|Greek transmission]]) in [[Gupta India]] and [[Tang China]].{{efn|1=It was transmitted to China in the 8th century by Manichaeans, via the country of [[Kangju|Kang]] (a Central Asian polity near [[Samarkand]]).
Tang-era adoption is documented in the writings of the Chinese Buddhist monk [[I Ching (monk)|Yi Jing]] and the Ceylonese Buddhist monk [[Amoghavajra|Bu Kong]].
According to the Chinese encyclopedia ''[[Cihai]]'' ({{Lang|zh-hans|辞海}}), there is some evidence that the system had been adopted twice, the first time already in the 4th century ([[Jin dynasty (265–420)|Jin dynasty]]), based on a reference by a Jin era astrologer, Fan Ning ({{Lang|zh-hant|范寧}} / {{Lang|zh-hans|范宁}}).
The ''Cihai'' under the entry for "seven luminaries calendar" ({{Lang|zh-hant|七曜曆}} / {{Lang|zh-hans|七曜历}}, ''qī yào lì'') has: "method of recording days according to the seven luminaries [{{Lang|zh|七曜}} ''qī yào'']. China normally observes the following order: Sun, Moon, Mars, Mercury, Jupiter, Venus, and Saturn. Seven days make one week, which is repeated in a cycle. Originated in ancient Babylon (or ancient Egypt according to one theory). Used by the Romans at the time of the 1st century CE, later transmitted to other countries. This method existed in China in the 4th century. It was also transmitted to China by Manichaeans in the 8th century from the country of Kang ({{Lang|zh|康}}) in Central Asia."<ref>{{cite web |title=Japanese Days of the Week: the 'Seven Luminaries' |url=http://www.cjvlang.com/Dow/dowjpn.html |website=Days of the Week in Chinese, Japanese, Vietnamese & Mongolian |publisher=cjvlang}}</ref>}}{{citation needed|date=June 2017}}
The Babylonian system was received by the Greeks in the 4th century BCE (notably via [[Eudoxus of Cnidus]]). Although some sources, such as the Encyclopædia Britannica,<ref>{{cite web |title=Week |url=https://www.britannica.com/science/week |website=Encyclopædia Britannica |publisher=Encyclopædia Britannica, Inc. |access-date=20 March 2024|quote=The Babylonians named each of the days after one of the five planetary bodies known to them (Mercury, Venus, Mars, Jupiter, and Saturn) and after the Sun and the Moon, a custom later adopted by the Romans.}}</ref> state that the Babylonians named the days of the week after the five planets, the sun, and the moon, many scholars disagree. [[Eviatar Zerubavel]] says, "the establishment of a seven-day week based on the regular observance of the Sabbath is a distinctively Jewish contribution to civilization. The choice of the number 7 as the basis for the Jewish week might have had an Assyrian or Babylonian origin, yet it is crucial to remember that the ancient dwellers of Mesopotamia themselves did not have a seven-day week."{{sfnp|Zerubavel|1989|loc=[https://books.google.com/books?id=Cd5ZjRsNj4sC&pg=PA14 p. 9]}} The astrological concept of [[planetary hours]] is an innovation of Hellenistic astrology, probably first conceived in the 2nd century BCE.{{sfnp|Zerubavel|1989|loc=[https://books.google.com/books?id=Cd5ZjRsNj4sC&pg=PA14 p. 14]}}

The seven-day week was widely known throughout the [[Roman Empire]] by the 1st century CE,<ref name=":2">{{cite book |url=https://books.google.com/books?id=PeVLAQAAQBAJ&pg=PA89|title=Written Space in the Latin West, 200 BCE to 300 CE |last1=Keegan |first1=Peter |last2=Sears |first2=Gareth |last3=Laurence |first3=Ray |date=12 September 2013 |publisher=A&C Black |isbn=9781441123046|language=en}}</ref> along with references to the Jewish Sabbath by Roman authors such as [[Seneca the Younger|Seneca]] and [[Ovid]].<ref>{{cite book |url=https://books.google.com/books?id=e3ijDgAAQBAJ&pg=PA21|title=Jesus in Q: The Sabbath and Theology of the Bible and Extracanonical Texts |last=So |first=Ky-Chun |date=6 April 2017 |publisher=Wipf and Stock Publishers |isbn=9781498282116 |language=en}}</ref> When the seven-day week came into use in Rome during the early imperial period, it did not immediately replace the older eight-day [[nundinal cycle|nundinal]] system.<ref>{{cite book |last1=Brind'Amour |first1=Pierre |title=Le calendrier Romain :Recherches chronologiques |date=1983 |publisher=Editions de l'Universitá d'Ottawa |isbn=2760347028 |pages=256–275 |language=fr}}</ref> The nundinal system had probably fallen out of use by the time Emperor [[Constantine the Great|Constantine]] adopted the seven-day week for official use in CE 321, making the [[Sunday|Day of the Sun]] ({{lang|la|dies Solis}}) a legal holiday.<ref>{{cite book |last1=Schaff |first1=Philip |title=History of the Christian Church Vol. III |date=1884 |publisher=T&T Clark |location=Edinburgh |page=[https://archive.org/details/historychristia01schagoog/page/n299 380] |url=https://archive.org/details/historychristia01schagoog|access-date=15 March 2019}}</ref>

===Achaemenid period===
The [[Zoroastrian calendar]] follows the Babylonian in relating the 7th, 14th, 21st, and 28th of the 29- or 30-day lunar month to [[Ahura Mazda]].<ref name="TSZ">Boyce, Mary (ed. & trans.). ''Textual Sources for the Study of Zoroastrianism''. University of Chicago Press, 1984, p. 19-20.</ref>
The forerunner of all modern Zoroastrian calendars is the system used to determine dates in the [[Achaemenid Empire|Persian Empire]], adopted from the Babylonian calendar by the 4th century BCE.

[[Frank Senn|Frank C. Senn]] in his book ''Christian Liturgy: Catholic and Evangelical'' points to data suggesting evidence of an early continuous use of a seven-day week; referring to the Jews during the [[Babylonian captivity]] in the 6th century BCE,<ref name="Senn 1997">{{cite book
| last = Senn
| first = Frank C.
| title = Christian Liturgy: Catholic and Evangelical
| publisher = Fortress Press
| year = 1997
| url = https://books.google.com/books?id=g5c7C2rQzU0C
| isbn = 978-0-8006-2726-3}}</ref> after the destruction of the [[Temple of Solomon]].
While the seven-day week in Judaism is tied to [[Genesis creation narrative|Creation account]] in the [[Book of Genesis]] in the [[Hebrew Bible]] (where [[Elohim|God]] creates the heavens and the earth in six days and rests on the seventh; Genesis 1:1-2:3,<ref>{{bibleverse||Genesis|1:1–2:3}}</ref> in the [[Book of Exodus]], the fourth of the [[Ten Commandments]] is to rest on the seventh day, ''[[Shabbat]]'', which can be seen as implying a socially instituted seven-day week), it is not clear whether the Genesis narrative predates the [[Babylonian captivity]] of the Jews in the 6th century BCE. At least since the [[Second Temple Judaism|Second Temple period]] under Persian rule, Judaism relied on the seven-day cycle of recurring [[Sabbath]]s.<ref name="Senn 1997"/>

Tablets{{citation needed|date=April 2015}} from the Achaemenid period indicate that the [[lunation]] of 29 or 30 days basically contained three seven-day weeks, and a final week of eight or nine days inclusive, breaking the continuous seven-day cycle.<ref name=ere/>
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.<ref name=ere/>

Difficulties with [[Friedrich Delitzsch]]'s [[origin theory]] connecting Hebrew ''[[Shabbat]]'' with the Babylonian [[lunar cycle]]<ref name=landau>{{cite book
|url=https://archive.org/stream/sabbath00land/sabbath00land_djvu.txt|title=The Sabbath
|author=Landau, Judah Leo
|publisher=Ivri Publishing Society, Ltd
|access-date=26 March 2009
|location=[[Johannesburg, South Africa]]
|pages=2, 12
}}</ref> include reconciling the differences between an unbroken week and a lunar week, and explaining the absence of texts naming the lunar week as ''Shabbat'' in any language.<ref name=orr>{{cite book
|chapter-url=https://books.google.com/books?id=Tn4PAAAAYAAJ&pg=PA2630
|title=The International Standard Bible Encyclopedia
|editor=Orr, James
|editor-link=James Orr (theologian)
|page=2630
|chapter=Sabbath: Critical Theories
|author=Sampey, John Richard
|publisher=Howard-Severance Company
|year=1915}}</ref>

===Hellenistic and Roman era===
{{Main|Nundinae}}

In [[Hellenistic Judaism|Jewish sources]] by the time of the [[Septuagint]], the term "Sabbath" ({{langx|el|Σάββατον|Sábbaton}}) by [[synecdoche]] also came to refer to an entire seven-day week,<ref>''Strong's Concordance'', ''4521''.</ref> the interval between two weekly Sabbaths. [[Parables of Jesus|Jesus's parable]] of the [[Pharisee and the Publican]] ([https://www.biblegateway.com/passage/?search=luke+18%3A12 Luke 18:12]) describes the Pharisee as fasting "twice in the week" ({{langx|el|δὶς τοῦ σαββάτου|dis tou sabbatou}}). In the account of the women finding the tomb empty, they are described as coming there "toward the one of the sabbaths" ({{langx|el|εἰς μίαν σαββάτων, τῇ μιᾷ τῶν σαββάτων}});<ref>Matthew 28:1, Mark 16:2</ref> translations substitute "week" for "sabbaths".

The ancient Romans traditionally used the eight-day [[nundinum]] but, after the [[Julian calendar]] had come into effect in 45 BCE, the seven-day week came into increasing use. For a while, the week and the nundinal cycle coexisted, but by the time the week was officially adopted by [[Constantine I (emperor)|Constantine]] in 321 CE, the nundinal cycle had fallen out of use. The association of the [[days of the week]] with the Sun, the Moon and the five planets visible to the naked eye dates to the [[Roman era]] (2nd century).{{sfnp|Zerubavel|1989|loc=[https://books.google.com/books?id=Cd5ZjRsNj4sC&pg=PA45 p. 45]}}<ref name="Senn 1997"/>

The continuous seven-day cycle of the days of the week can be traced back to the reign of [[Augustus]]; the first identifiable date cited complete with [[day of the week]] is 6 February 60 CE, identified as a "[[Sunday]]" (as {{lang|la|viii idus Februarius dies solis}} "eighth day before the ides of February, day of the Sun") in a Pompeiian graffito. According to the (contemporary) Julian calendar, 6 February 60 was, however, a [[Wednesday]]. This is explained by the existence of two conventions of naming days of the weeks based on the [[planetary hours]] system: 6 February was a "Sunday" based on the sunset naming convention, and a "Wednesday" based on the sunrise naming convention.<ref>'' Nerone Caesare Augusto Cosso Lentulo Cossil fil. Cos. VIII idus Febr(u)Arius dies solis, luna XIIIIX nun(dinae) Cumis, V (idus Februaries) nun(dinae) Pompeis''.<br/>{{cite book |author=Robert Hannah |chapter=Time in Written Spaces |editor1=Peter Keegan |editor2=Gareth Sears |editor3=Ray Laurence |title=Written Space in the Latin West, 200 BCE to 300 CE |publisher=A&C Black |year=2013 |page=[https://books.google.com/books?id=PeVLAQAAQBAJ&pg=PA89 89]}}</ref>

===Islamic concept===
According to Islamic beliefs, the seven-day a week concept started with the creation of the universe by Allah. [[Abu Hurayra|Abu Huraira]] reported that [[Muhammad]] said: Allah, the Exalted and Glorious, created the clay on Saturday and He created the mountains on Sunday and He created the trees on Monday and He created the things entailing labour on Tuesday and created light on Wednesday and He caused the animals to spread on Thursday and created Adam after 'Asr on Friday; the last creation at the last hour of the hours of Friday, i. e. between afternoon and night.<ref>{{Cite web|title=Sahih Muslim 2789 - Characteristics of the Day of Judgment, Paradise, and Hell - كتاب صفة القيامة والجنة والنار - Sunnah.com - Sayings and Teachings of Prophet Muhammad (صلى الله عليه و سلم)|url=https://sunnah.com/muslim:2789|access-date=17 July 2021|website=sunnah.com}}</ref>

===Adoption in Asia===
====China and Japan====
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 (265–420)|Jin dynasty]], while diffusions from the [[Manichaeism|Manichaeans]] are documented with the writings of the Chinese Buddhist monk [[I Ching (monk)|Yi Jing]] and the Ceylonese or Central Asian Buddhist monk [[Amoghavajra|Bu Kong]] of the 7th century ([[Tang dynasty]]).

The Chinese variant of the planetary system was brought to Japan by the Japanese monk [[Kūkai]] (9th century). 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 Period]] (1868–1912).

====India====
The seven-day week was known in India by the 6th century, referenced in the [[Pancasiddhantika#Pancha-Siddhantika|Pañcasiddhāntikā]].{{Citation needed|date=April 2013}} Shashi (2000) mentions the [[Yuga Purana|Garga Samhita]], which he places in the 1st century BCE or CE, as a possible earlier reference to a seven-day week in India. He concludes "the above references furnish a [[terminus ad quem]] (viz. 1st century) The [[terminus post quem|terminus a quo]] cannot be stated with certainty".<ref>{{cite book
| last = Shashi
| first = Shyam Singh
| title = Encyclopaedia Indica India, Pakistan, Bangladesh Vol. 76 Major dynasties of ancient Orissa: India, Pakistan, Bangladesh
| publisher = Anmol Publications PVT. LTD
| year = 2000
| pages = 114–115
| url = https://books.google.com/books?id=nhYgnKipe-QC
| isbn = 978-81-7041-859-7}}</ref><ref>{{cite book
| author = Pandurang Vaman Kane
| title = [[History of Dharmaśāstra]]
| date = 1930–1962
}}</ref>

===Christian Europe===
{{Further|Holy Week|Easter Week}}

The seven-day weekly cycle has remained unbroken in [[Christendom]], and hence in [[Western history]], for almost two millennia, despite changes to the [[Coptic calendar|Coptic]], [[Julian calendar|Julian]], and [[Gregorian calendar|Gregorian]] calendars, demonstrated by the date of [[Easter]] Sunday having been traced back through numerous [[computus|computistic tables]] to an Ethiopic copy of an early Alexandrian table beginning with the Easter of 311 CE.<ref>{{cite book
| last = Neugebauer
| first = Otto
| title = Ethiopic astronomy and computus
| publisher = Verl. d. Österr. Akad. d. Wiss
| year = 1979
| isbn = 978-3-7001-0289-2}}
</ref><ref>{{cite web |url=http://www.bbc.co.uk/religion/0/20394641 |author=Jayne Lutwyche |date=22 January 2013 |title=Why are there seven days in a week? |publisher=BBC |work=Religion & Ethics |quote=The Roman context of the spread of Christianity meant that Rome contributed a lot to the structure and calendar of the new faith}}</ref>

A tradition of divinations arranged for the days of the week on which certain feast days occur develops in the early medieval period. There are many later variants of this, including the German {{lang|de|Bauern-Praktik}} and the versions of ''[[Erra Pater]]'' published in 16th- to 17th-century England, mocked in [[Samuel Butler (poet)|Samuel Butler]]'s ''[[Hudibras]]''. South and East Slavic versions are known as ''koliadniki'' (from ''koliada'', a loan of Latin {{lang|la|calendae}}), with Bulgarian copies dating from the 13th century, and Serbian versions from the 14th century.<ref name="Ryan380">William Francis Ryan, ''The Bathhouse at Midnight: An Historical Survey of Magic and Divination in Russia'', Penn State Press, 1999
[https://books.google.com/books?id=S3qJMMYH6VYC&pg=PA380 p. 380].</ref>

Medieval Christian traditions associated with the lucky or unlucky nature of certain days of the week survived into the modern period. This concerns primarily [[Friday]], associated with the [[crucifixion of Jesus]]. [[Sunday]], sometimes personified as [[Anastasia the Patrician|Saint Anastasia]], was itself an object of worship in Russia, a practice denounced in a sermon extant in copies going back to the 14th century.<ref name="Ryan383">William Francis Ryan, ''The Bathhouse at Midnight: An Historical Survey of Magic and Divination in Russia'', Penn State Press, 1999
[https://books.google.com/books?id=S3qJMMYH6VYC&pg=PA383 p. 383].</ref>

[[Sunday]], in the ecclesiastical numbering system also counted as the {{lang|la|feria prima}} or the first day of the week; yet, at the same time, figures as the "[[The eighth day (Christian)|eighth day]]", and has occasionally been so called in Christian liturgy.{{efn|1=This is just a reflection of the system of [[ordinal numbers]] in the Greek and Latin languages, where today is the "first" day, tomorrow the "second" day, etc. Compare the [[nundinal cycle]] (literally "nine-days" cycle, describing an [[eight-day week]]) of the Roman calendar, or the [[Resurrection of Jesus]] (after a period of less than 48 hours) being described (in texts derived from Latin) as happening on the "third day".}}

[[Justin Martyr]] wrote: "the first day after the Sabbath, remaining the first of all the days, is called, however, the eighth, according to the number of all the days of the cycle, and [yet] remains the first."<ref>{{cite web |url=http://www.earlychristianwritings.com/text/justinmartyr-dialoguetrypho.html |author=Peter Kirby |title=Saint Justin Martyr: Dialogue with Trypho |website=Early Christian Writings}}</ref>

A period of eight days, usually (but not always, mainly because of Christmas Day) starting and ending on a Sunday, is called an [[octave (liturgy)|octave]], particularly in [[Roman Catholic liturgy]]. In German, the phrase {{lang|de|heute in acht Tagen}} (literally "today in eight days") can also mean one week from today (i.e. on the same weekday). The same is true of the Italian phrase {{lang|it|oggi otto}} (literally "today eight"), the French {{lang|fr|à huitaine}}, and the Spanish {{lang|es|de hoy en ocho}}.