Aries

Aries occupies the first thirty-degree arc of the tropical zodiac, from 0 to 30 degrees of ecliptic longitude measured from the March equinox. It holds a distinction none of the other eleven signs shares: the equinox is the start of Aries ^{1 bk. I ch. 11}. The other three cardinal points, the June solstice, the September equinox and the December solstice, sit at 90, 180 and 270 degrees, counted onward from this one. Every other sign boundary in the tropical scheme is defined relative to Aries’s zero point; Aries’s zero point is defined relative to nothing but the Earth and the Sun.

Names, and what the earliest one says

The Babylonian constellation is MUL.LÚ.ḪUN.GÁ, Akkadian agru, “the hired man”: a human agricultural labourer, hired for a wage ². The Greek name is Krios, “ram”, and the Latin Aries follows the Greek. The animal that gives the modern sign its familiar picture, and the golden-fleeced ram of the Argonaut story later attached to it, belong to the Greek layer and are not in the Babylonian figure at all ³.

The direction of the change runs opposite to Virgo’s. There, an agricultural image, a furrow, was reinterpreted as a human figure, a maiden. Here, a human figure, a hired labourer, was reinterpreted as an animal. Both signs carry a Babylonian occupational image under a Greek mythological one, and the two moves run in opposite directions across the same human/non-human line Virgo.

Three candidates for the shift

Rogers, an astronomer synthesising Assyriological scholarship, states plainly that “there is no Mesopotamian record of it as a constellation” ⁴: no surviving source treats the Ram itself as a Mesopotamian constellation. The farming-calendar figure named above is listed in MUL.APIN under a name that attaches Dumuzi’s to it from the outset, transliterated by Rogers as mul lu-Hun-ga, d-Dumuzi, with the mul and the d raised as determinatives rather than read as part of the words ⁴. That attachment bears on the third mechanism below.

Rogers offers three candidate mechanisms for what replaced the labourer, in his own order, and ranks none of them as settled. First, Ea’s ram’s-head symbol, already present in his iconography in neighbouring constellations, may have supplied the animal. Second, the labourer’s own name may have carried it: in lu-hun-ga, “Lu” meant sheep, and in Babylon the same root produced both Agru, “farm-labourer”, and Immeru, “sheep”, hence, on this reading, the Ram. Third, and “perhaps most likely” in Rogers’s own assessment, is Dumuzi the shepherd: a dying-and-rising god, and so a fitting custodian of the spring equinox, who unlike Mesopotamia’s other major gods was never illustrated, a silence Rogers finds consistent with how few pictographs of Aries survive ⁴. He adds one further data point rather than a fourth mechanism: a ram similar to Aries appears on Kassite boundary-stones beside Shala’s ear of corn, the figure behind Virgo, so, he suggests, “perhaps this symbol was transferable among the fertility deities” ⁴. By his reckoning the sign had come to contain the spring equinox by around 2200 BC.

The second mechanism, the pun on lu, also circulates in non-scholarly compilations; it is printed here on the footing of Rogers’s peer-reviewed paper.

Technical attributions

Aries is ruled by Mars, the first entry in the scheme that gives each planet a domicile counting outward from the Sun’s and Moon’s signs at Leo and Cancer Mars; the whole arrangement, and the parts of it that are textually contested, is set out at Essential Dignity. The Sun holds its exaltation here, on a rationale Ptolemy states for the sign rather than for any particular degree within it; every exaltation degree in the scheme, this one included, descends from an older Mesopotamian stream that is not Ptolemy’s own contribution, a point this entry does not repeat.

Aries also opens the face sequence. The faces run in Chaldean order beginning with Mars at zero Aries, straight through all twelve signs without resetting at a sign boundary ^{5 bk. I6 bk. I}. Because thirty-six is not divisible by seven, the cycle does not close on itself: the last face of Pisces and the first face of Aries are both held by Mars. Aries sits at the seam of that cycle, the point where it restarts.

The sign and the constellation

The IAU constellation Aries is narrower than the tropical sign named for it, spanning about 24.73 degrees of ecliptic longitude against the sign’s fixed 30. Because the tropical zero point is anchored to the equinox rather than to any star, and because precession has carried the equinox well over twenty degrees away from where it stood when the tropical and sidereal frames last coincided, zero degrees Aries no longer falls inside the boundaries of the constellation carrying its name Precession of the Equinoxes. The sign is defined by an event in the Earth-Sun geometry, and has not pointed at its own constellation for a long time.

Seven of the twelve ecliptic constellations are narrower than the thirty-degree sign named for them, and Aries sits in the middle of that group: wider than Cancer, Libra, Aquarius and Scorpius, narrower than Capricornus and Gemini. That width is computed from where the 1930 boundary lines were drawn ⁷; Delporte tabulated no such figure, and it is a fact about that cataloguing decision alone. The full account of the three frames this creates, and why the mismatch is not evidence for a missing thirteenth sign, is at Three Reference Frames.