
Dodekatemorion (sing.) or dodekatemoria (pl) (or dodecatemorion, etc.)
The literal meaning of the Greek word dodekatemorion is 'twelfth part', for which reason it is sometimes used in Greek texts to refer to the 12 signs of the zodiac, or increments of 12 degrees. More specifically, it is descriptive of an ancient Babylonian principle which attributes extended meaning to zodiac signs and degrees that are divided or multiplied by the number twelve, (based on the reasoning that since 12 is the number of the cosmos, its divisions and multiplications can be used to explore things at a microcosmic or a macrocosmic level). Through this, each sign is treated as a 'microzodiac' by division into twelve equal parts of 2˝°. To the Babylonians these were known as zittu (the Akkadian word for 'share' or 'part').
The dodekatemoria of
the zodiac sign Aries
The multiplication of a planet's degree position by twelve also creates an associated point in the actual zodiac (also called its dodekatemorion / zittu), which is considered influential upon other planets or any sensitive chartpoints that it falls upon. For example, if a planet is located at 10° Taurus, its degree position (10) is multiplied by twelve to obtain 120°, and its dodekatamorion is placed 120° ahead of it in the zodiac. What appear to be conflicting accounts of the placement of this point are offered by Firmicus (Mathesis, I.XIII) and Paulus of Alexandrinus (Introductory Matters, 22):
 The method of Firmicus projects the result of the calculation from the beginning of the sign in which the planet is positioned, so (starting the count of 120° from 0° Taurus) the dodekatemorion of 10° Taurus falls at 0° Virgo.
 The method of Paulus projects the result of the calculation from the position of the planet, so (starting the count of 120° from 10° Taurus) the dodekatemorion of 10° Taurus is 10° Virgo. Another way to get the same result (which is how Paulus describes it) is to multiply the degree position by 13 instead of 12 and then start the count from the beginning of the sign  the multiplication by 13 simply accommodates the fact that the count is including the position of the planet.
Commentators often describe these two approaches as being distinguished by multiplication of 12 or 13, but this misses a fundamental point: the symbolism is always determined by the act of multiplying or dividing by 12; what differs according to alternate accounts, is the logic of where the count ought to begin. Both approaches have a meaningful rationale, and it is probable that they originated as two separate techniques (one emphasizing multiplication, the other emphasizing division) which became strongly associated with each other due to their shared descriptive name and symbolic dependency on the number 12.
To explain more fully: on the one hand it seems logical to project the result of the calculation from the point being progressed, which is what Paulus does; though by making reference to multiplication by 13 he obscures the reason why this makes sense: which is simply because it adds the result of the 12fold multiplication to the position of the planet. Paulus gives the example of 11° Aries: the multiplication of 11° by 12 equals 132°, adding these degrees to 11° Aries obtains the result he describes: 23° Leo.
This approach concurs with the description of the technique found in Babylonian texts. Francesca Rochberg's book In the Path of the Moon: Babylonian Celestial Divination and Its Legacy shows how the multiplication of a degree position by twelve is described in cuneiform texts (p.157  I have omitted her mathematical notations):
In other sources in which the connection between astrology and magic is documented, incantations are assigned to the twelve zittu of the zodiac. As shown by Neugebauer and Sachs, these two texts provide further evidence that the Greek method of computing dodekatemoria was based on the method found in cuneiform material. The method may be formulated in the following way: Given a position in the zodiac expressed in degrees of a zodiacal sign, a second position in the zodiac may be obtained by multiplying the degrees by 12 and adding the result to the first longitude.
Rochberg then gives the interpretation of a few lines from a table in a cuneiform source which demonstrates this (p.158):
In line 1, the position given is I 10 (= Aries 10°). Aries 10° is associated with Leo 10°, which is called "Leo of Aries". Following the abovementioned method of computing dodekatemoria, we multiply 10° (the degrees of Aries) by twelve and travel that many degrees (120°) along the zodiac from Aries to the sign Leo. Adding n degrees of the zodiacal sign ["n degrees" = number of degrees of the planet], here 10, we reach Leo 10° as given … [in the table … (Rochberg then notes how the same procedure yields the rest of the results)].
On the other hand, the method of calculation described by Firmicus (which commences projection from the start of the sign) provides neat association with the 2˝° divisions of the signs which create the 'zodiac within a zodiacsign' effect. Each sign begins the distribution by claiming the first 2˝° as its own, and the following parts are assigned to the rest of the signs following the natural order of the zodiac, as shown in the table below. Babylonian texts show that this microzodiac was used to generate detailed symbolic signification of such things as cities, plants, trees stones, etc. (see Rochberg, p.156157).
The use of these 2˝° divisions to calculate the dodekatamoria is reported to be a development of Hindu atrology, (where each partition is called a 'dwadasamsa' or 'dwad'), although reference to their use in measuring the dodekatamoria is found in the 39th chapter of Porphyry's Introduction to the Tetrabiblos. Porphyry does not explain their use in interpretation, but in regard to their calculation he tells us:
The dodecatemory of the Moon is taken properly, first by looking at how many degrees of the sign the Moon has, of that [number] measure off 2˝ degrees [through] the succeeding [signs], and wherever the number leaves off, there is the dodecatemory. For example, let the Moon have 13 [degrees] of Aries: give to Aries 2˝, to Taurus 2˝, [to Gemini 2˝,] to Cancer 2˝, to Leo 2˝, then the dodecatemory is in Virgo, the domicile of Mercury. The dodecatemory of the Sun is taken similarly...
Porphyry the Philosopher, tr. by James Holden (AFA, 2009), p.29.
The above table offers easy reference for the calculation described by Porphyry. Consider the example of the Moon at 19° Pisces: we see at a glance from the table that the first 2˝° of Pisces belong to the dodekatamorion of Pisces, the next 2˝° belong to that of Aries, and so on until we get to the 8th column where we see that the degrees between 17˝ and 20 of Pisces belong to the dodekatemorion of Libra, governed by Venus. The symbolic significance of this approach, and how it leads to a similar result as that obtained by Firmicus' method of multiplying degree positions to find a planet's dodekatemoria is explained by Konrad Klawikowski:
If a planet is around onethird of the way through the sign Taurus, sitting at 11°, then we should also consider that it is around onethird of the way through the "microzodiac" that runs through Taurus. We find this in two ways:
 First, in the manner Porphyry suggests: we count out 2˝° portions starting at the beginning of the sign the planet occupies, giving one sign to each portion, and stopping when we reach the planet itself. In the example above of 11° Taurus, we start at 0° Taurus and count 2˝° until we reach 11°  that is four full portions (full signs in our system) which leaves us in Virgo (Taurus  Gemini  Cancer  Leo).
 Second, we can arrive at the same place simply by multiplying the number of degrees of the planet by 12 (as Firmicus suggests) and adding the number to the beginning of the sign occupied by the planet. In our example, we take 11 and multiply it by 12 giving us 132. If we add 132° to the beginning of Taurus, we have four full signs of 30° and a remainder of 12°, so we come to 12° Virgo.
Paulus tell us that the dodekatemorion of the benefic planets bring good fortune if they fall upon the position of the Sun, Moon, Mercury, the angles, Part of Fortune, etc. The 60th chapter of Rhetorius also has a detailed passage on the meaning of contacts made between one planet's dodekatemorion and the position of other planets, part of which reads:
If the Moon's dodecatemorion is in trine to her, it signifies renowned persons; but if it is in opposition, the opposite of this and inglorious persons. But if the Moon's dodecatemorion falls into her opposition in a quadrupedal sign, and she is aspected by Mars, it makes those who are eaten by wild beasts. ... And if [the aspect] is to the [star] of Saturn, the mother will be subjugated or a foreigner and the [native] himself will be placed in subjection. And the great nativities suffer a loss of livelihood, especially by night. And if [the aspect] falls on the [star] of Mercury, [it makes] learned persons, those who have been educated. And if to Jupiter, august, godlike persons. And if to Venus, friendly, cheerful, merry persons…
And similarly too in the case of the other stars if the dodecatemorian is thus. If the dodecatemorion of Saturn and the dodecatemorian of Mars falls into the place of the Moon or of the Sun [it is] not good...
Rhetorius the Egyptian, tr. by James Holden (AFA, 2009), p.110111.
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© Deborah Houlding, 2016 (with thanks to Konrad Klawikowski for his helpful input).
 