Editing Zodiac (section)

=== Early history ===
As early as the 14th century BC a complete list of the 36 Egyptian [[decan]]s was placed among the hieroglyphs adorning the tomb of [[Seti I]]; they figured again in the temple of [[Ramesses II]], and characterize every Egyptian astrological monument. Both the famous zodiacs of [[Dendera]] display their symbols, identified by [[Karl Richard Lepsius]].<ref>{{EB1911 |wstitle=Zodiac |volume=28 |page=997 |first=Agnes Mary |last=Clerke |author-link=Agnes Mary Clerke|inline=1}}</ref>

[[File:Antoninus Pius Drachm showing a Zodiac wheel.jpg|thumb|400px|Roman Egyptian coin of [[Antoninus Pius]] (dated year 8 of his reign or 145 AD) showing his portrait and a Zodiac wheel with the busts of [[Helios]] and [[Selene]] in the center]]
[[File:Beit Alpha.jpg|thumb|A sixth-century mosaic zodiac wheel in synagogue [[Beth Alpha]] incorporating Greek-Byzantine elements, Israel]]
[[File:F4.v. zodiac circle with planets - NLW MS 735C.png|thumb|Zodiac circle with planets, {{circa|1000}} – ''NLW MS 735C'']]

The division of the ecliptic into the zodiacal signs originates in [[Babylonian astronomy]] during the first half of the [[1st millennium BC]]. The zodiac draws on stars in earlier [[Babylonian star catalogues]], such as the [[MUL.APIN]] catalogue, which was compiled around 1000 BC. Some constellations can be traced even further back, to Bronze Age ([[Old Babylonian Empire]]) sources, including [[Gemini (constellation)|Gemini]] "The Twins", from {{langx|sux|𒀯𒈦𒋰𒁀𒃲𒃲|translit=<sup>MUL</sup>MAŠ.TAB.BA.GAL.GAL}} "The Great Twins"; [[Cancer (constellation)|Cancer]] "The Crab", from {{langx|sux|𒀯𒀠𒇻|translit=<sup>MUL</sup>AL.LUL}} "The Crayfish", among others.<ref name=Rogers_1998/><ref>{{cite book
 | chapter=History of the Sumerian, Accadian, Assyrian, and West Semitic calendars
 | title=Babylonian menologies and the Semitic calendars
 | first=S. | last=Langdon | author-link=Stephen Herbert Langdon | year=1935
 | series=The Schweich Lectures of the British Academy, 1933
 | publisher=Oxford University Press | publication-place=London
 | url=https://gospelstudies.org.uk/biblicalarchaeology/pdf/schweich-lectures/1933_babylonian-menogies_langdon.pdf
 | access-date=2024-01-15 }}</ref>

Around the end of the fifth century BC, [[Babylonia]]n astronomers divided the ecliptic into 12 equal "signs", by analogy to 12 schematic months of 30 days each. Each sign contained 30° of [[celestial longitude]], thus creating the first known celestial coordinate system. According to calculations by modern astrophysics, the zodiac was introduced between 409 and 398 BC, during [[Achaemenid Empire|Persian rule]],<ref>{{cite book
 | last=Ossendrijver
 | first=Mathieu
 | date=2013
 | chapter=Science, Mesopotamian
 | title=The Encyclopedia of Ancient History
 | doi=10.1002/9781444338386.wbeah21289
 | isbn=9781405179355
 | chapter-url=https://amor.cms.hu-berlin.de/~ossendrm/encyc-ancient-hist-2013-ossendrijver.pdf
 | access-date=2022-04-18
 | archive-date=16 June 2022
 | archive-url=https://web.archive.org/web/20220616052542/https://amor.cms.hu-berlin.de/~ossendrm/encyc-ancient-hist-2013-ossendrijver.pdf
 | url-status=live
 }}</ref> and probably within a very few years of 401 BC.<ref>{{Cite journal | last=Britton | first=John P. | date=2010 | title=Studies in Babylonian lunar theory: part III. The introduction of the uniform zodiac | journal=Archive for History of Exact Sciences | volume=64 | issue=6 | pages=617–663 | jstor=41134332 | doi=10.1007/S00407-010-0064-Z | s2cid=122004678 | quote=[T]he zodiac was introduced between −408 and −397 and probably within a very few years of −400.}}</ref> Unlike modern astrologers, who place the beginning of the sign of [[Aries (astrology)|Aries]] at the position of the Sun at the [[Equinox (celestial coordinates)|vernal equinox]] in the [[Northern Hemisphere]] ([[March equinox]]), Babylonian astronomers fixed the zodiac in relation to stars, placing the beginning of [[Cancer (astrology)|Cancer]] at the "Rear Twin Star" ([[Pollux (star)|β Geminorum]]) and the beginning of [[Aquarius (astrology)|Aquarius]] at the "Rear Star of the Goat-Fish" ([[Delta Capricorni|δ Capricorni]]).<ref>{{cite book | last=Steele | first=John M. | date=2012 | orig-year=2008 | title=A Brief Introduction to Astronomy in the Middle East | publisher=Saqi | place=London | edition=electronic | isbn=9780863568961 }}</ref>

Due to the [[precession of the equinoxes]], the time of year the Sun is in a given constellation has changed since Babylonian times, as the point of March equinox has moved from [[Aries (constellation)|Aries]] into [[Pisces (constellation)|Pisces]].<ref>{{Cite web | last=Plait | first=Phil | date=26 September 2016 | title=No, NASA hasn't changed the zodiac signs or added a new one | website=Bad Astronomy | url=http://www.slate.com/blogs/bad_astronomy/2016/09/26/no_nasa_didn_t_change_your_astrological_sign.html | access-date=2 October 2016 | archive-date=2 October 2016 | archive-url=https://web.archive.org/web/20161002070120/http://www.slate.com/blogs/bad_astronomy/2016/09/26/no_nasa_didn_t_change_your_astrological_sign.html | url-status=live }}</ref>

Because the divisions were made into equal arcs of 30° each, they constituted an ideal system of reference for making predictions about a planet's longitude. However, Babylonian techniques of observational measurements were in a rudimentary stage of evolution.<ref name=Sachs/> They measured the position of a planet in reference to a set of "normal stars" close to the ecliptic (±9° of latitude). The normal stars were used as observational reference points to help position a planet within this ecliptic coordinate system.<ref>{{cite book | last=Aaboe | first=Asger H. | author-link=Asger Aaboe | title=Episodes from the Early History of Astronomy | place=New York | publisher=Springer | date=2001 | pages=37–38 | isbn=9780387951362 }}</ref>

In [[Babylonian astronomical diaries]], a planet position was generally given with respect to a zodiacal sign alone, though less often in specific degrees within a sign.<ref name="Rochberg">{{cite journal | last=Rochberg | first=Francesca | author-link=Francesca Rochberg | date=1988 | title=Babylonian Horoscopes | journal=Transactions of the American Philosophical Society | volume=88 | issue=1 | pages=i–164 | jstor=1006632 | doi=10.2307/1006632 | publisher=American Philosophical Society }}</ref> When the degrees of longitude were given, they were expressed with reference to the 30° of the zodiacal sign, i.e., not with a reference to the continuous 360° ecliptic.<ref name="Rochberg" /> In astronomical [[ephemerides]], the positions of significant astronomical phenomena were computed in [[sexagesimal]] fractions of a degree (equivalent to [[Minute and second of arc|minutes and seconds of arc]]).<ref>{{cite book | last=Aaboe | first=Asger H. | author-link=Asger Aaboe | title=Episodes from the Early History of Astronomy | place=New York | publisher=Springer | date=2001 | pages=41–45 | isbn=9780387951362 }}</ref> For daily ephemerides, the daily positions of a planet were not as important as the astrologically significant dates when the planet crossed from one zodiacal sign to the next.<ref name="Rochberg" />