Capricorn
Capricorn occupies the tenth thirty-degree arc of the tropical zodiac, from 270 to 300 degrees of ecliptic longitude, measured from the March equinox. Zero degrees of Capricorn marks the December solstice in the tropical frame, which is the reason a line of terrestrial latitude carries this sign’s name; what has happened to that line since is taken up below.
Names, and what the earliest one says
The Babylonian constellation is MUL.SUḪUR.MÁŠ, “the Goat-Fish,” attested in the star catalogues by about 1000 BCE 1. The same hybrid is attested far earlier: “Ea’s goat-fish” is “first seen on a seal of Ur just before 2000 BC,” on the account of John H. Rogers, an astronomer synthesising the Assyriological editions of MUL.APIN and the Mesopotamian seal and boundary-stone corpus 2. The same figure recurs on boundary stones across the second millennium BCE as a symbol of Ea 2. On this account the Ea association is what the goat-fish is, from the seal onward 2. Ea’s association with fresh water generally, and with the Tigris and Euphrates in particular, is attested independently of this one constellation 3. The Greek name is Aigokeros, “goat-horned,” and the Latin Capricornus keeps the same compound 4.
Unlike the furrow that became a maiden or the composite god that became a plain archer, this is a case of continuity: the Greek name describes the same hybrid the Babylonian figure already was, and the hybrid is the interesting part. A goat with a fish’s tail is not an animal that exists, and the fact that this specific invented creature crossed from Mesopotamia to Greece to Rome to the modern zodiac wheel without being replaced by something more natural is the more notable feature of this sign than any element of its later symbolism.
Correction
Commonly saidCapricorn was originally simply a goat, and the fish tail is a later decorative addition to the figure.
The order runs the other way, and there is no point in the record where a plain goat is what the evidence shows. The hybrid is present in the standardised Babylonian star catalogues 1, and on Rogers’s reading it is already the figure on the seal of Ur, cut just before 2000 BCE, nearly two thousand years before the Hellenistic period: “a Goat-Fish hybrid… not a goat” 2. The modern symbol has kept the fish tail. Of the twelve signs, Capricorn is the one whose image has drifted least, because what happened to it across two thousand years of transmission left the hybrid standing. Where Scorpio lost its claws to a neighbouring sign and Sagittarius lost its composite form to a plain archer, Capricorn lost almost nothing: the fish tail is still there.
Rogers’s own structural point ties this sign directly to its neighbours at the same solstice: “Ea at the winter solstice was supported with his Goat-fish on one side and Fishes on the other” Pisces, with Ea himself becoming the water-pourer Aquarius 2. In this scheme the goat-fish is one of Ea’s own symbols, flanking him.
Technical attributions
| Domicile | Saturn |
|---|---|
| Detriment | Moon |
| Exaltation | Mars, at 28 degrees |
| Fall | Jupiter, at 15 degrees |
| Triplicity | Earth. By day Venus, by night Moon, participating Mars |
| Bounds (Egyptian) | Mercury 0-7Jupiter 7-14Venus 14-22Saturn 22-26Mars 26-30 |
| Faces | Jupiter 0-10, Mars 10-20, Sun 20-30 |
Capricorn is Saturn’s first domicile, opposite Cancer, which the Moon rules; Mars is exalted here, the sign’s other notable placement, and Cancer covers the other end of that opposition along with the matching solstice problem taken up below. Capricorn also carries the earth triplicity, shared with Taurus and Virgo, part of the fivefold scheme of domicile, exaltation, triplicity, bound and face first stated in a datable Hellenistic text 5 bk. I. The full apparatus, including the one row where the ancient authorities disagree, is set out in Essential Dignity, and Saturn covers why the two signs furthest from Cancer and Leo fell to the slowest-moving planet in the traditional scheme. Capricorn is also one of the four cardinal signs, the group that opens a season, with Aries, Cancer and Libra; its own season-opening role is the December solstice taken up below.
The sign and the constellation, and the tropic that shares its name
Tropical Capricorn is a fixed thirty-degree arc; the IAU constellation Capricornus spans 27.83 degrees of ecliptic longitude, closer to the sign’s own width than most of its neighbours. The general relationship between the two kinds of object, and why treating them as the same claim leads to error, is set out at Three Reference Frames.
The terrestrial tropic of Capricorn is a related but separate case of the same underlying fact. It marks the southernmost latitude, about 23.4 degrees south of the equator, at which the Sun can appear directly overhead, which happens at the December solstice, and it was named at a time when the December solstice Sun stood among the stars of Capricornus. Precession has since moved the solstice point out of the constellation whose name the line still carries, exactly as it has moved the June solstice out of Cancer on the opposite side of the year; Cancer gives that half of the pair, and Precession of the Equinoxes covers the mechanism responsible for both. Maps and atlases keep the name fixed when it was given, while the latitude itself follows the slowly changing obliquity.
References
- Hermann Hunger, John Steele. The Babylonian Astronomical Compendium MUL.APIN. Scientific Writings from the Ancient and Medieval World. London: Routledge, 2019. find a copy (catalogue search) recordpeer reviewed
The current standard edition. Some listings show 2018 for the first printing. Use this and Rochberg 2004 for Babylonian star names and figures, not the popular compilations that circulate on astrology sites.
- Francesca Rochberg. The Heavenly Writing: Divination, Horoscopy, and Astronomy in Mesopotamian Culture: Cambridge University Press, 2004. find a copy (catalogue search) recordpeer reviewed
Indispensable for the Mesopotamian material and for how it reached Greek astrology.
- Nicholas Campion. A History of Western Astrology, Volume I: The Ancient and Classical Worlds: Continuum, 2009. ISBN 9781441127372 recordscholarly
The standard single narrative survey. Volume I first appeared as The Dawn of Astrology, Hambledon Continuum, 2008. The subtitle is "The Ancient and Classical Worlds", not "The Ancient World"; the shortened form is widely miscited.
- Claudius Ptolemy, trans. F. E. Robbins. Tetrabiblos. Loeb Classical Library 435. Cambridge, MA: Harvard University Press, 1940 (composed c. 150 CE). bk. I. find a copy (catalogue search) recordprimary source
The standard English reference and the chapter-numbering scheme this site adopts and names. Non-Robbins reprints number the chapters differently, so every locus here is given as Robbins numbering.
- John H. Rogers. Origins of the ancient constellations: I. The Mesopotamian traditions. Journal of the British Astronomical Association 108(1), 1998, 9-28. https://articles.adsabs.harvard.edu/pdf/1998JBAA..108....9R record Accessed 2026-07-30.scholarly
The reference for the Mesopotamian iconography. It traces every zodiacal figure from the early pictograph seals through the boundary stones to MUL.APIN and the Greek sky-map, and it covers precisely the material an edition of MUL.APIN does not: which deity a figure represented, how it was pictured, and on which dated object. Read in full from the scan linked above before it was cited here. Characterise it when citing, as this site does with Brennan. Rogers is an astronomer synthesising Assyriological scholarship for astronomers, not an Assyriologist: his own sources are Hunger and Pingree's MUL.APIN edition, Gössmann's Planetarium Babylonicum, van der Waerden, and Black and Green. The paper is refereed, heavily cited, and explicit that it is offering inferences in places, which it marks with "I suggest" and "perhaps". Those marks are the author's own and should survive into any entry that uses the passage. A companion Paper II covers the Mediterranean and Greek traditions and is not held here.
Further reading
- Jeremy Black, Anthony Green. Gods, Demons and Symbols of Ancient Mesopotamia: An Illustrated Dictionary, 1992.