Editing Zodiac (section)

=== Hellenistic and Roman era ===
[[File:Dendera.jpg|thumb|left|The 1st century BC [[Dendera zodiac]] (19th-century engraving)]]
The Babylonian star catalogs entered [[Greek astronomy]] in the 4th century BC, via [[Eudoxus of Cnidus]].<ref name=Rogers_1998/>
Babylonia or [[Chaldea]] in the Hellenistic world came to be so identified with astrology that "Chaldean wisdom" became among [[Greeks]] and [[Ancient Rome|Romans]] the synonym of [[divination]] through the [[planets]] and [[star]]s. [[Hellenistic astrology]] derived in part from Babylonian and [[Ancient Egyptian astronomy|Egyptian astrology]].<ref>{{cite thesis | url=http://www.astrologer.com/aanet/pub/transit/jan2005/babylonian.htm | last=Powell | first=Robert | title=Influence of Babylonian Astronomy on the Subsequent Defining of the Zodiac | year=2004 | degree=PhD | archive-url=https://web.archive.org/web/20090521081306/http://www.astrologer.com/aanet/pub/transit/jan2005/babylonian.htm | archive-date=21 May 2009 }} summarized by anonymous editor.</ref> [[Horoscopic astrology]] first appeared in [[Ptolemaic Kingdom|Ptolemaic Egypt]] (305 BC–30 BC). The [[Dendera zodiac]], a relief dating to {{circa|50 BC}}, is the first known depiction of the classical zodiac of twelve signs.

The earliest extant Greek text using the Babylonian division of the zodiac into 12 signs of 30 equal degrees each is the ''Anaphoricus'' of [[Hypsicles of Alexandria]] (fl.{{nbsp}}190{{nbsp}}BC).<ref>{{ Cite book | last=Montelle | first=Clemency | editor-last=Steele | editor-first=John M. | date=2016 | title=The Circulation of Astronomical Knowledge in the Ancient World | chapter=The ''Anaphoricus'' of Hypsicles of Alexandria | pages=287–315 | series=Time, Astronomy, and Calendars: Texts and Studies | volume=6 | publisher=Brill | location=Leiden | isbn=978-90-0431561-7 }}</ref> Particularly important in the development of Western horoscopic astrology was the astrologer and astronomer [[Tetrabiblos|Ptolemy]], whose work ''Tetrabiblos'' laid the basis of the [[Western astrological tradition]].<ref>{{cite book | last=Saliba | first=George | author-link=George Saliba | year=1994 | title=A History of Arabic Astronomy: Planetary Theories During the Golden Age of Islam |location=New York | publisher=New York University Press | page=67 | isbn=978-0-8147-8023-7 }}.</ref> Under the Greeks, and Ptolemy in particular, the planets, Houses, and signs of the zodiac were rationalized and their function set down in a way that has changed little to the present day.<ref>{{cite book |last1=Parker |first1=Julia |first2=Derek |last2=Parker |year=1990 |title=The New Compleat Astrologer|isbn=978-0517697009 |publisher=Crescent Books |location=New York, NY|page=16 }}</ref> Ptolemy lived in the 2nd century AD, three centuries after the discovery of the [[precession]] of the equinoxes by [[Hipparchus]] around 130 BC. Hipparchus' lost work on precession never circulated very widely until it was brought to prominence by Ptolemy,<ref name="Springer">{{cite book|last1=Graßhoff|first1=Gerd|title=The History of Ptolemy's Star Catalogue|date=1990|publisher=Springer|isbn=9780387971810|page=73}}</ref> and there are few explanations of precession outside the work of Ptolemy until late Antiquity, by which time Ptolemy's influence was widely established.<ref name=Geminos>{{cite book|last1=Evans|first1=James|last2=Berggren|first2=J. Lennart|title=Geminos's Introduction to the Phenomena|date=2006|publisher=Princeton University Press|isbn=069112339X|page=113}}</ref> Ptolemy clearly explained the theoretical basis of the western zodiac as being a [[tropical astrology|tropical coordinate system]], by which the zodiac is aligned to the equinoxes and solstices, rather than the visible constellations that bear the same names as the zodiac signs.<ref name="Ptolemy's Tetrabiblos">{{cite book|last1=Ashmand|first1=J. M.|title=Ptolemy's Tetrabiblos|publisher=Astrology Classics|page=37 (I.XXV)|year=2011|isbn=978-1461118251}}</ref>