The Thema Mundi

by Douglas Noblehorse

I want to acknowledge the work of Robert Schmidt, Ellen Black and Project Hindsight, whose translation and reformulation of the ancient Hellenistic astrological body of work has been exhaustive and meticulous, and is an ongoing enterprise. The greater portion of the material here is a restatement of their Conclave 2006 presentation - with additional material from their Conclave 2007. I would also like to acknowledge the subsequent input and clarifications (from online forums and courses, private emails and in-person conversations) kindly offered by those working with Project Hindsight and others, such as Bill Johnston, Curt Manwaring, Alan White, Chris Brennan, Merre Garstin, Patrick Watson and Nick Dagan Best.


The Thema Mundi is a Natural Wheel dating from the Hellenistic era that illustrates fundamental astrological principles. In addition, it reveals the inner geometrical elegance that gives these fundamentals their meaning and definition.

For instance, when we think of Mars, we also think of Aries and Scorpio. To a lesser extent we think of Capricorn. We also think of squares. The Thema Mundi shows why we do that. It goes deeper than that though, because the Thema Mundi shows why we should perhaps think of the 5th, 6th, 7th and 10th houses as well.

Even though the Thema Mundi is a Hellenistic technique that is over 2000 years old, it still has primary relevance for astrologers today. If you practice horoscopic astrology - and that’s just about everyone, except for those who practice Chinese, Tibetan, Meso-American or Babylonian Omen astrology - then you are a direct astrological descendant of the original horoscopic astrology known today as Hellenistic. However, my goal in presenting the Thema Mundi, is to provoke fresh insights into familiar fundamentals that are second nature to most astrologers.

The Thema Mundi graphic is my restatement of a Hellenistic teaching tool showing the underlying interrelationships between planets, signs, houses and aspects.

The Thema Mundi comes to down to us through Hellenistic astrologers such as Paulus Alexandrinus, Firmicus Maternus (both flourished during the 4th Century CE), Thrasyllus (1st Century CE, and friend of the Roman Emporor Tiberius), and earlier mythical astrologers such as Anubio, Nechepso and Petosirus. My usage of the word mythical however implies unknown, as opposed to unreal or fictional. The true authors of the books attributed to these names remain unknown. The greatest of these mythical astrologers was Hermes Trismegestus, who some say was an Egyptian, and others say was either a contemporary of the biblical Abraham, or even Abraham himself. It is traditionally thought that Hermetic philosophy comes from the writings of Hermes Trismegestus. Interestingly, one of three major disciplines or paths of Hermetic Philosophy is the study of astrology.

Before we can begin to explore the Thema Mundi, I’d like to quickly present some basic Hellenistic astrological concepts - that of Sect as well as some basic planetary meanings.

Planetary Significations

This is a brief listing of fundamental planetary significations, illustrating the core principles or archetypes that give rise to the various, yet related significations of each planet. They are as follows:

The Sun - Selection, including the mind and wisdom (the ability to select what is useful and what is not), and action (the ability to select a course of action that benefits the native).

The Moon - Accumulation, as in gathering resources and inclusion. This basic nature underpins the Modern view of the Moon as supportive and nurturing, qualities which could not exist without a prior gathering of resources.

Mercury - Contestation, as in challenging, or competing. Also destabilization. Mercury likes to question everything.

Venus - Reconciliation, and unification. Out of Sect, Venus can bring about self-destructive temptations.

Mars - Severance and separation. Mars can act in the interest of the native by clearing away obstacles, an example of using Mars as a weapon or tool. Generally though Mars subtracts from the native, bringing about separations of all kinds. Because of this Mars specifically signifies retrogradation, when something is lost or subtracted from the native. Mars can signify resistance to change.

Jupiter - Stabilization and confirmation. Secondary significations include the idea of alliances.

Saturn - Rejection and exclusion. Saturn is also deception - which, as Robert Schmidt is fond of pointing out, involves acting as well as oratory, especially oration meant to persuade or deceive, as in spin-control or propaganda.


Of fundamental and central importance in Hellenistic astrology is the concept of the Lights, the Sun and the Moon. Everything in the horoscope starts with the initial consideration of these two points. In the Modern era astrologers focus on and acknowledge the Sun as central to the chart, largely de-emphasizing the role of the Moon. After all, modern logic stresses that the Sun is the center of the Solar System. Without the Sun life on Earth would not exist! Yet, it has been recently shown that without the Moon also, life could not exist on Earth. This seems to support the geocentric point of view, where the Sun and Moon are equal in apparent size (giving rise to the eclipse phenomenon) and reinforces the the Hellenistic viewpoint of the equal importance of both the Sun and the Moon.

So the first initial consideration in an astrological chart is called Sect, which is a Greek concept that divides the planets into two sets, with one grouping generally having freer rein to pursue its agenda, while the other party of planets has somewhat less latitude to act. The Diurnal Sect is made up of the Sun, Jupiter and Saturn. Jupiter is warm and so belongs to the Diurnal Sect. Saturn as a malefic, cold planet is thought to be moderated by Diurnal warming. The Nocturnal set is made up of the Moon, Venus and Mars. Likewise, Venus as a cool, benefic planet joins with the Moon. Mars, as a malefic, hot planet is moderated by Nocturnal cooling. Mercury crosses the line between the two and can belong to either Sect depending on its position in the chart. If Mercury rises before the Sun, it is Diurnal. If it rises after the Sun, it is Nocturnal. The Sect of the chart determines which Sect is dominant, either Diurnal or Nocturnal.

The Sect of the chart is determined by the position of the Sun, either above the horizon or below the horizon - which is defined by the Ascendant/Descendant axis. If any portion of the Sun’s disk is above the horizon (especially at sunrise or sunset) the chart is Diurnal and the Sun is the Sect Light. Otherwise, the chart is Nocturnal (and the Moon is the Sect Light) because the Sun is below the horizon. Additionally, the chart hemisphere that the Sun is in determines the Sect of the hemisphere - during the day when the Sun is above the horizon, the upper hemisphere is Diurnal, the lower Nocturnal. At night when the Sun is below the horizon, the opposite is in effect - the lower hemisphere is Diurnal while the upper is Nocturnal. To take it a step further, each sign is either Diurnal or Nocturnal, with the masculine, positive-polarity expressive signs being Diurnal, the feminine, negative-polarity receptive signs being Nocturnal.

Ideally, Jupiter and Saturn function best when located in the same hemisphere with the Sun, and Venus and Mars are happiest when with the Moon. Additionally, the Sun, Jupiter and Saturn are most content when in masculine signs, and the Moon, Venus and Mars function best in feminine signs. If a particular planet meets all of its Sect qualifications, then it is said to be in hayz - which is an Islamic definition, not a Hellenistic one. Benefic planets of the Sect in Favor work diligently in the interests of the native. Malefic planets of the Sect in Favor, while remaining malefic, generally work to the benefit of the native, clearing away opposition for instance, or excluding and rejecting influences not in the native’s interest. Benefic planets of the Sect Out of Favor still aid the native, but may also provide hard-to-resist temptations not in the native’s best interest. Malefic planets of the Sect Out of Favor can be real pills, causing destructive headaches for the native that impede his or her progress.

In the real world though, things are different - Diurnal planets are found in the Nocturnal hemisphere or in Nocturnal signs, or both, while Nocturnal planets land in Nocturnal signs in the Diurnal hemisphere, etc. This is where the astrologer’s skill and experience in assessing this fundamental balance of power in the chart comes in. It can sometimes be the case where planets defect to the opposite Sect, either in specific instances as the occasion warrants or over longer periods of cooperation. If a planet has closer ties to the opposing Sect and is involved closely by aspect with them, then it’s possible for that planet to contribute to the opposing Sect’s agenda. For example, if the Sun in a Diurnal chart is in Aversion (the Hellenistic term for an inconjunct or quincunx configuration) to both Jupiter and Saturn, who are below the horizon in a Nocturnal sign, closely conjunct the Moon, opposing Mars and Trine Venus, then it’s likely Jupiter and Saturn concern themselves more with the Nocturnal Sect than they do their Diurnal responsibilities to the Sun, who they cannot “see”.

Thema Mundi

The Thema Mundi is the idealized chart for the Beginning of the World - although the ancient Hellenistic astrologers understood this chart as figurative, not literal. Modern astrologers think of the archetypal astrological chart with Aries rising, but at least during the early Hellenistic period this figurative chart had Cancer rising - and there are important philosophical elements built in that support the choice of Cancer as the horoskopos, or Ascendant. (See the Thema Mundi figure.)

To begin with, the Cancer ingress marks the Summer solstice, the longest day of the year. The first House is the place of Life and Breath - Cancer is a nurturing, supportive sign, while the Moon as Domicile Lord represents inclusion and a gathering in of energies. The next sign is the domicile of Leo, the warmest part of the year, mid-summer in the Northern hemisphere. These two signs then are the fulcrum of the Thema Mundi. In fact, in the earlier Persian astrological tradition, the Sun was Domicile Lord of Cancer as well as Leo. The Moon was thought to move too fast to be Lord of a sign. At any rate, the Sun and the Moon as the two Lights sit in partnership in their Lordships over Leo and Cancer.

Other possible reasons why Cancer is assigned the first house horoskopos position could be the Mesopotamian belief that human souls enter and exit the earthly plane through the solstices - a belief itself that might be tied to a similar belief that the world begins and ends when all the planets line up in either Cancer or Capricorn, as pointed out by Chris Brennan. He also points to the beginning of the Egyptian New Year, which took place in the summer as the fixed star Sirius was heliacally rising.

Domicile Lords, or Sign Rulers

In assigning further Domicile Lords (the inner ring in the Thema Mundi illustration), notice that the signs on either side of Cancer and Leo are assigned to Mercury, namely the signs of Gemini and Virgo. One step further with Taurus and Libra, and we have Venus as Domicile Lord. Then comes Mars as Domicile Lord of Aries and Scorpio, Jupiter as Domicile Lord of Pisces and Sagittarius, and finally Saturn as Domicile Lord of Aquarius and Saturn.

Looking deeper into this chart, you can see that the Venus-ruled signs are in a Sextile relationship to the Light-ruled signs - Taurus is Sextile Cancer, Libra is Sextile Leo. Like Venus which is seen as the lesser Benefic, the Sextile is regarded as the lesser beneficial aspect. Similarly, Mars-ruled Aries is Square to Cancer, and Scorpio squares Leo. Mars, the lesser Malefic corresponds to the Square as the lesser Malefic aspect. Jupiter-ruled Pisces trines Cancer, with Sagittarius trining Leo. The greater beneficial Trine aspect walks hand in hand with Jupiter, the greater Benefic. And finally, Saturn-ruled Aquarius opposes Leo, with Capricorn opposing Cancer. Saturn the greater Malefic corresponds to the opposition as the greater Malefic aspect.

Regarding the various Domicile lordship axes, we notice that the Lights are involved in an axial relationship with Saturn, Mercury with Jupiter, and Venus with Mars. If we consider the basic principles of these planetary axial pairs, we notice that their meanings are diametrical, or opposing. While the Sun selects, Saturn rejects. While the Moon includes, Saturn excludes. While Mercury destabilizes and challenges, Jupiter stabilizes and confirms. Finally, while Venus reconciles and unifies, Mars severs and separates. In my opinion, it can be beneficial to examine the relationship between these pairs of planets in the charts that astrologers interpret. Certainly, if these planetary opposites are in conjunction or in opposition in a horoscope, the issues they bring up play a fundamental role in the native’s life. Perhaps this is what Thrasylllus meant when he said that all charts should be examined against the Thema Mundi!

Exaltation Lords

The center ring of the Thema Mundi graphic shows planetary exaltations. Here again there is an underlying elegance to the layout. Notice that a planet is Exalted in a sign whose Domicile Lord is of the opposite Sect, with two exceptions. This illustrates the planets that are Domicile Lord of two signs keep their Sect-related sign for themselves, sharing lordship only in those signs that are contrary to their basic Sect nature. For example, Nocturnal Mars is Domicile Lord of Diurnal Aries, sharing lordship by exaltation with the Diurnal Sun. Mars keeps Nocturnal Scorpio for itself, where no planet is exalted. Diurnal Jupiter is Domicile Lord of Nocturnal Pisces, sharing lordship by exaltation with Nocturnal Venus, keeping Diurnal Sagittarius for itself. Diurnal Saturn shares Nocturnal Capricorn with Nocturnal Mars, keeping Diurnal Aquarius for itself.

The first exception is Mercury Exalted in Virgo, where it is also Domicile Lord. However, this duality is certainly in keeping with Mercury’s innate duality and its ability to belong to either sect depending on position. The second case is the Moon’s exaltation in Taurus, whose Domicile Lord is Venus, both Nocturnal planets. Both the Moon and Venus are accommodating in nature, and so are receptive to one another. Nevertheless, Nocturnal Venus shares lordship of Diurnal Libra with Diurnal Saturn.

Planetary House Joys

Finally we come to the House Joys of the planets. The Sun finds it joy in the 9th House, Jupiter in the 11th House, and Saturn in the 12th House. Mercury finds its joy in the 1st House, the Moon in the 3rd House, Venus in the 5th House, and Mars in the 6th House. Notice that the Diurnal planets are above the horizon with the Sun, while the Nocturnal planets are below, with the Moon. And Mercury, as usual, sits in between!

The Sun finds its joy in the 9th House because traditionally the 9th House represents the King (not the 10th as in Modern astrology) and spiritual authority. This is perhaps the source of the Indian Jyotish assignment of the father (the Sun) to the 9th House. Jupiter likes the 11th House because in the 11th House we traditionally find the concepts of patronage, protection, and acquisition. This House also represents friendships, but more specifically friendships and group associations that offer benefits through patronage. Saturn is dark (being the dimmest of the observed planets) and so likes the seclusion of the 12th House. The 12th House is also Cadent and unconnected to the Ascendant (it’s not related to the Ascendant by any of the so-called Ptolemaic - which I will henceforward refer to as Hellenistic - aspects). In this House, the greater Malefic can do the least amount of damage.

Mercury likes the 1st House, because the 1st is life and breath and is the Helm of the horoscope, the steering mechanism. Mercury as communicator of messages functions well here. Furthermore, it’s interesting that the 1st House as Ascendant straddles both hemispheres, again reinforcing the dualistic nature of Mercury.

The Moon is comfortable in the 3rd House, because the 3rd House is all that is comfortable and familiar in your immediate environment - sibilings, friends and neighbors, and socializing. It’s interesting to note that in either the Aries rising chart or the Cancer-oriented Thema Mundi, Mercury is Domicile Lord of the 3rd House. Mercury rules the rational mind, but it is the Moon that rules the irrational or instinctive mind, the familiar mental processes.

Venus and the 5th House? Is it too hard to see the association here? Parties, fun, enjoyment, sex. Need we say more?

Finally, in Hellenistic astrology, the 6th House traditionally showed enemies, as well as accidents and injuries. And so we have Mars, cause of injury and accident. Furthermore, the same logic that applied to Saturn applies to Mars. It was thought best to bury Mars in a Cadent House unconnected to the Ascendant. Mars is the lesser Malefic which is why it was assigned to the 6th - the 6th is marginally better than Saturn’s 12th because the 6th is in a Trine, or Trigonal configuration with the 10th House, which is second only to the Ascendant in importance.


In conclusion, the Hellenistic astrologers had a complete concise teaching tool in the Cancer-rising Thema Mundi. This simple chart alone encapsulates many of the fundamental principles of Hellenistic astrology, and serves as a handy teaching tool and an instant refresher course by virtue of its structure alone.

Just by quickly glancing at the Thema Mundi, astrologers of any experience level are quickly reminded of not only sign rulerships, but more importantly, why the signs/domiciles have the plantary lords that they have. Meditating further, one can also grasp the sect-related interplay between Domicile and Exaltation lordships as well as the sect-related structure of the planetary House Joys. Astute astrologers also appreciate the deeper meanings of the planetary significations - and their relationship to one another, as revealed by the aspectual and configurational relationships illustrated by the Thema Mundi.



Warm & Moist Benefic harmonizes with the Day
Cold & Dry Malefic is warmed by the Day


Cool & Moist Benefic harmonizes with the Night Hot & Dry Malefic is cooled by the Night

Diurnal or Nocturnal

Sect Status depends on Zodiacal Position

Diurnal - Rising Before the Sun; Lesser Zodiacal Degree than the Sun; Rudhyar’s Promethean Mercury

Nocturnal - Rising After the Sun; Greater Zodiacal Degree than the Sun; Rudhyar’s Epimethean Mercury

Planetary Core Meanings

The Sun - Selection, including the mind and wisdom (the ability to select what is useful and what is not), and action (the ability to select a course of action that benefits the native).

The Moon - Accumulation and inclusion, as in collecting and gathering resources. This basic nature underpins the view of the Moon as supportive and nurturing, qualities which could not exist without a prior gathering of resources. In a symbolic sense, the Moon collects the Sun’s Light, reflecting it to Earth. So too does the Moon absorb the efflux of the various planets, in turn transmitting it to the Earth plane.

Mercury - Contestation, as in challenging, or competing. Also destabilization. Mercury likes to question everything.

Venus - Unification and reconciliation. This is the foundation of relationship. Venus brings together things that are unconnected.

Mars - Severance and separation. Mars can act in the interest of the native by clearing away obstacles, an example of using Mars as a weapon or tool. Generally though Mars subtracts from the native, bringing about separations of all kinds. Because of this Mars specifically signifies retrogradation, when something is lost or subtracted from the native. Mars breaks connections.

Jupiter - Stabilization and confirmation. Secondary significations include the idea of alliances and patronages that benefit the native.

Saturn - Rejection and exclusion. Saturn denies and ignores. Saturn is also deception - which involves acting as well as oratory, especially oration meant to persuade or deceive, as in spin-control or propaganda.

The Thema Mundi © 2007 Quincunx Astrology