The logic behind triplicity rulers

Recently I’ve been thinking about triplicity rulers and wondering about the logic behind the different systems.  I first learned triplicity rulers from William Lilly’s Christian Astrology (1647) and later learned the Dorothean system from Dorotheus’ 1st century work Carmen Astrologicum.  The two systems have some similarities and some important differences.

As a refresher, here is the Dorothean system of triplicity rulers:

And here is Lilly’s more simplified version which he attributes to Ptolemy:

As you can see, Lilly assigns only two rulers to each triplicity (day and night rulers) whereas Dorotheus assigns three (day, night and participating rulers).  Both authors use the classical seven visible planets. It appears that Lilly has greatly simplified the Dorthean system by eliminating the “participating” ruler of the triplicity.  In addition, Lilly appears to have eliminated the day and night rulers of the water triplicity and used only the participating triplicity ruler, Mars.  In doing so, Lilly almost certainly introduced an erroneous understanding of Ptolemy into the astrology of his time.  Interestingly, Claude Dariot, a predecessor of Lilly (Christian Astrology, 1647), wrote a book in 1557 in which he gave VENUS as the day ruler of the Water triplicity and MARS as the night ruler.  Like Lilly, Dariot did not use the participating rulers.

Here is a table I put together to illustrate the logic behind the triplicity rulers:


William Lilly appears to have selected the domicile ruler of the fixed sign of each triplicity as its principal triplicity ruler by day.

  • For diurnal Fire (Aries, Leo, Sagittarius), Lilly’s day ruler is the Sun, which rules fixed Leo.  This leaves Jupiter as the night ruler.  Mars cannot be used because it is of the nocturnal sect and is quite malefic in a day chart.
  • For nocturnal Earth (Taurus, Virgo, Capricorn), Lilly’s day ruler is Venus because Taurus is a fixed sign.  His night ruler is the Moon which is exalted in Taurus and is the leader of the sect.
  • For diurnal  Air (Gemini, Libra, Aquarius), Lilly’s day ruler is Saturn because Aquarius is a fixed sign.  Even though Saturn is a malefic, it is a member of the day sect, and its more positive attributes are likely to manifest in a day chart.  Lilly’s night ruler is Mercury, which rules Gemini.  Venus cannot be used because it is of the nocturnal sect.
  • For nocturnal Water (Cancer, Scorpio, Pisces), Lilly’s day ruler is Mars because Scorpio is a fixed sign. His night ruler is also Mars, but there is little logic in his position because both Venus and the Moon are available to be used as triplicity rulers of Water.

Dorotheus uses the domicile rulers of the fixed signs as well as the exaltations of the planets in his system of triplicity rulers.  The sect of the planets is also of paramount importance.

  • For diurnal Fire (Aries, Leo, Sagittarius), Dorotheus uses as his day ruler the SUN which is exalted in Aries and also rules the fixed sign Leo.  Jupiter (domicile ruler of Sagittarius) becomes the night ruler.  Mars cannot be used because it is of the nocturnal sect.  Saturn, as the remaining member of the diurnal sect but which is not a domicile ruler in Fire, becomes the participating ruler.
  • For nocturnal Earth (Taurus, Virgo, Capricorn), Dorotheus uses as his day ruler VENUS which rules the fixed sign Taurus, and as his night ruler the MOON which is exalted in Taurus.  Mars, which is exalted in Capricorn, becomes the participating ruler.  [It is notable that Mercury rules Virgo and is exalted there, but does not appear as a triplicity ruler of the Earth signs, probably because Mercury’s sect varies according to its position relative to the Sun.   Pingree, however, in his translation of the Arabic version of the Carmen Astrologicum does have the phrase, “in Virgo there is also a participation of Mercury,” so it appears that either Dorotheus or his Arabic translators considered the idea of Mercury as a triplicity ruler of the earth signs.  At least one modern practitioner of Hellenistic astrology, Rafael Gil Brand, uses Mercury in this way.]
  • For diurnal  Air (Gemini, Libra, Aquarius), Dorotheus uses as his day ruler SATURN, which is both exalted in Libra and ruler of the fixed sign Aquarius.  Mercury, as ruler of the air sign Gemini, becomes the night ruler even though it is of variable sect because there is no other choice among the possible planets to rule this sect.  Jupiter, as the remaining member of the diurnal sect but which is not a domicile ruler in Air, becomes the participating ruler.
  • For nocturnal Water (Cancer, Scorpio, Pisces),  Dorotheus uses as his day ruler VENUS which is exalted in Pisces, and as his night ruler MARS which rules the fixed sign Scorpio.  Mars cannot be a day ruler because it belongs to the nocturnal sect and is quite malefic in a day chart.  The Moon, which rules Cancer, becomes the participating ruler because it is neither exalted nor the domicile ruler of a fixed sign in the Water triplicity.

It seems to me that Dorotheus’ system has a tightly reasoned logic, whereas Lilly’s system makes little astrological sense, especially as regards the water triplicity.  Why would an astrologer grant primary dignity to Mars as a day ruler of the water signs in a diurnal chart in which Mars is the malefic of the contrary sect and capable of such grand maleficence? Because Scorpio is a member of the water triplicity, Mars has some dignity as a participating triplicity ruler, and this does serve to mitigate its malevolence a bit in a day chart; but Mars remains the malefic of the contrary sect and an extremely problematic planet during daylight hours.


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About Anthony Louis

Author of books about astrology and tarot, including TAROT PLAIN AND SIMPLE, HORARY ASTROLOGY, and THE ART OF FORECASTING WITH SOLAR RETURNS.
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7 Responses to The logic behind triplicity rulers

  1. 2converse says:

    Thanks Anthony.
    Really tight piece of analysis.

  2. Hi Del,
    Glad you enjoyed it.

  3. Tom says:

    Hi Tony

    Well, now what about the simplest and most logical system of triplicity rulers of all: Our buddy Morinus? He uses the planet that has two rulerships in an element as the day ruler. The ruler of the cardinal sign as the night ruler, and the remaining ruler of that element as the triplicity ruler. For example Fire: The Sun rules the fixed sign Leo and is exalted in the fire sign Aries so he is the day ruler. Mars is the ruler of Cardinal Aries, so he is the night ruler. Jupiter rules the mutable Sagittarius and is “left over” so to speak, and he is the participating or third ruler. Earth: Mercury is exalted and rules Virgo, so the day ruler. Saturn is the ruler of cardinal earth, Capricorn and is the night ruler. Venus rules fixed Taurus and is the participating ruler.

    Why not do the last two as well? Air: Saturn rules Aquarius and is exalted in Libra so the day ruler. Venus rules Libra and is the night ruler. Mercury rules mutable Gemini and is the participating ruler. Finally Water: Jupiter rules Pisces and is exalted in Cancer and is the day ruler. Moon rules cardinal Cancer so is the night ruler. Mars rules fixed Scorpio.

    The beauty of this system is that it can be worked out on the spot without memorizing a table.

    Unlike Lilly, this is not based on sect. It is based on the two essential dignities that are superior to triplicity. Morinus didn’t use the terms or faces claiming they were “Arab fantasies.” While this is often used to brand him as anti-Arab, it is probably closer to the truth that he found nothing in the terms or faces that were in nature. For Morinus, Astrology was natural. If it didn’t exist in nature, it didn’t belong in astrology whether it was put there by the Arabs (Greeks really) or anyone else.

    His sytem then is perfectly consistent with his other teachings and determines the third essential dignity not by the weak almost accidental dignity of sect, but with the two more powerful dignities of domicile rulership and exaltation.

    Hope this finds you well

    Tom Callanan

    • Hi Tom,
      Great to hear from you. I am familiar with Morin’s system ( and have found it to have merit, but for some reason it never caught on among astrologers. The more I study astrology, the more impressed I have become with the importance of the idea of sect as a fundamental building block. For this reason, I tend to favor the Dorothean triplicity rulers over that of Morin. I have not used the Morinus system in many horary charts, so I can’t speak from experience. The Dorothean system works quite well. It may be that Morinus works equally well, and his system is clearly quite logical as you point out.

      Regarding Morin’s argument that astrology must be grounded in nature, there can be no greater grounding that the daily alternation of day and night, which is the basis of the idea of sect. And as Ben Dykes points out about the decans:
      “Before the Greek invention of horoscopic astrology in the first few centuries B.C., the Babylonian and Egyptian traditions of star-gazing and omens did not focus so exclusively on the zodiac. As the heavens turned from east to west (called primary motion in astrology), different constellations rose, culminated, and fell, depending on one’s latitude and the season of the year. Originally, the Egyptians associated 36 constellations with the calendar (non-zodiacal).” (

      As you note”Morinus didn’t use the terms or faces claiming they were “Arab fantasies,” yet he ignores the fact that domicile rulers and exaltations of planets are Babylonian “fantasies” based on the prevailing magical-religious traditions of ancient Mesopotamia.

      Had Morin been more aware of the origins and history of astrology, he might have found the Dorothean triplicity rulers quite logical and consistent with what is found in nature.

  4. Tom says:

    Actually Morin was aware of the earlier systems, but he attributed them to the wrong people. He correctly identified Ptolemy’s two triplicity ruler system, but incorrectly identified the Dorothean system as having been originated by the Arabs..Nevertheless he was not only aware of those systems but also of Schoener’s and I’m not going to touch that part right now..

    Morin did not consider sect to be unnatural. He said Ptolemy et al had that wrong, too. Mars is a day planet not a night planet and Saturn is a night planet not a day planet. Therefore, their triplicity systems are out of whack. Once we accept that premise, the rest falls into place quite … uhhhh … naturally.

    “Nothing in the whole of astrology as so agitated my understanding as that the greater part of the old astrologers, but especially the Arabs, on all the sublunar effects have especially judged from the trigons, and their rulers, …” – Book 15 Chapter 6

    When he says “Arabs” he is referring to Dorotheus, but doesn’t know it. He makes his case for Mars being diurnal in Book 13, the earliest book of Astrologia Gallica to be translated into English that I know of. Then in book 15 Chapter 6, after accepting that Mars belongs in the diurnal sect he deduces the reasons for his new system. It’s easier to just point out that he uses the two strongest essential dignities to deduce the triplicities than go into his entire argument. I don’t even know that I could adequately summarize it.

    The Arabs, the real ones – not the ones of his imagination, made extensive use of the Dorothean triplicity rulers in natal astrology and Morin’s system isn’t all that much different except here and there. However if we use triplicity rulers the way the Arabs did, again the real ones, those few differences could make a significant difference. For example let’s say Aquarius is on the 7th cusp in a day chart. The married life is then divided into thirds. Using Dorotheus the first third of the married life would be ruled by Saturn, the second by Mercury and the last by Jupiter. So a lousy start, a second third determined by the condition of Mercury (could go either way), and finally good things happen. Morinus, however would say the first part is also ruled by Saturn, the second by Venus, and the last by Mercury. Someone with a statistical bent might be able to compare such things, but it would be an enormous task, assuming objective delineations of the condition of the planets in each chart and an objective delineation of the marriage.

    I like Morin’s system because I can figure out which triplicity ruler I need without resorting to a chart. I know – that’s not a great reason. But if something just doesn’t make sense, then I can look up the other system and try that, assuming there is a difference. It’s an interesting problem, but there are so few charts where one system or the other is a “make it or break it” delineation, that it might not be worth the effort of sorting them out.

    Then of course we can’t ignore Schoener, or can we?

    • Hi Tom,
      Your comments are great and very thought provoking. I focused on Lilly and Dorotheus because, as I read the current literature, they are the two systems most in vogue nowadays. That doesn’t necessarily make them correct, but it does speak to their popularity. As you know, I’m a great fan of Morinus and have read him extensively and experimented with his chart examples. Morin’s system of triplicity rulers has seemed effective when I’ve used it, but I’ve currently settled on the Dorothean system partly because of its antiquity and its esteemed position in the history of astrology.

      Schoener’s system seems to me to be a variant of Dortheus. As I recall, Schoerner divided the triplicity rulers as follows:
      Fire: Sun – Jupiter – Mars (Mars instead of Saturn)
      Earth: Moon – Venus – Saturn (instead of Venus – Moon – Mars)
      Air: Saturn – Mercury – Jupiter (same as Dorotehus)
      Water: Venus – Mars – Moon (same as Dorotheus)
      I have no idea whether these were due to transcription errors in translation, or whether Schoerner had a rationale for switching things around. I’m also unaware of contemporary astrologers who follow this system, though there may be some.

      Regarding statistical demonstrations of validity, I’m sure they would prove disappointing for the reasons outline by Geoffrey Cornelius in his book The Moment of Astrology. Our astrology is a metaphorical system based on the religious symbolic imagery of the ancient cultures of Babylon, Egypt and Greece. It is not a science any more than poetry or fine art is a science, and thus exists at a level of discourse which is outside the realm of the scientific method. From this point of view, Morin’s struggle to make astrology one of the natural sciences was doomed to failure.


      • Tom says:

        Agreed on the science bit. I only mentioned it because I read a paper a couple of years ago that argued, if there was a way to use statistical analysis to attempt to validate astrology. Morin’s theory of determinations might be it. I only mentioned statistics in the context of comparing one set of triplicity rulers with another. It’s probably too daunting a task and might not reveal much of value, if it could be done at all.

        All the best..

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