The Master of the Nativity: Finding the Ruler of the Chart

The Master of the Nativity: Finding the Ruler of the Chart

In episode 205 astrologers Chris Brennan and Leisa Schaim present a lecture on the ancient method of identifying the overall ruler of a birth chart, called the Master of the Nativity.

While in modern times astrologers tend to refer to the ruler of the Ascendant as the ruler of the chart, in ancient Greco-Roman astrology the method for determining the ruler of the chart was much more complex.

There are references to the master of the nativity in many of the surviving astrological texts from the Hellenistic astrology tradition, although there are not many surviving discussions about how to calculate it.

The approach that we present in this lecture is derived from chapter 30 of Porphyry’s Introduction to the Tetrabiblos, which is itself derived from a lost work of definitions by Antiochus of Athens.

During the course of the lecture we talk about how to calculate the predominator (epikratētōr), the master of the nativity (oikodespotēs geneseōs), the co-master or joint master of the nativity (sunoikodespotēs), and the lord of the nativity (kurios).

We also discuss various questions such as the arguments for and against having one overall chart ruler, the use of the master of the nativity to identify the guardian spirit or daimōn by ancient astrologers and philosophers, and the use of this doctrine to identify more important placements in a chart.

This lecture was originally presented by Chris at the Northwest Astrological Conference in May of 2017, and then again at the United Astrology Conference in May of 2018. We decided to re-record the lecture for the podcast now in order to give a more careful and deliberate presentation of the material, a better recording, and in order to open up this research to a wider audience.

Thanks to all of the patrons who support the podcast on an ongoing basis and made this episode possible through our page on Patreon. If you enjoy the episode and want to help support the production of future episodes while getting access to additional bonus content, then please consider becoming a patron.

This episode is available in both audio and video versions below.

First I will outline the calculations for the different rulers of the nativity presented in this lecture, and then you will find the recordings available at the bottom of the page.

How to Calculate the Rulers of the Birth Chart According to Porphyry

Here are the rules for calculating the different rulers of the birth chart that we review in this podcast, based on chapter 30 of Porphyry’s Introduction.

The Rulers of the Nativity

There are four different rulers of the nativity that are important to pay attention to:

  1. Predominator (epikratētōr)
  2. Master of the Nativity (oikodespotēs)
  3. Co-Master or Joint Master of the Nativity (sunoikodespotēs)
  4. Lord of the Nativity (kurios)


In order to find the Master of the Nativity you must first find the Predominator, since the Predominator is the one who designates the Master. The Predominator is typically one of the luminaries, as long as they are well-placed. If they are not, then it defaults to the Ascendant.

Here are Porphyry’s considerations for determining if one of the luminaries can become Predominator:

  • The luminary that belongs to the sect of the chart is preferred (Sun day day, Moon by night).
  • The luminary that is more angular is preferred over one that is in a less angular house.
  • The one that is more eastern in the chart (towards the rising sign) is preferred.
    • g. if the Sun is in the 1st house in a day chart, Sun is the Predominator.
    • Sun in the 9th with the Moon in the 1st, then Moon is Predominator.
  • If both luminaries are in cadent houses, then the Ascendant becomes Predominator.

Master of the Nativity

According to Antiochus and Porphyry there are two variant traditions for calculating the Master:

  1. The Master of the Nativity is the domicile lord of the Predominator.
    • The bound lord of the Predominator becomes the Co-Master of the Nativity.
  2. Others say that the bound lord of the degree of the Ascendant is the Master of the Nativity.
    • The domicile lord of the rising sign is the Co-Master of the Nativity.

Lord of the Nativity

Two separate approaches are given for the determination of the Lord of the Nativity:

First Approach

  1. The Lord is the domicile lord of the Midheaven, if this planet is angular. If it is not, then:
  2. The Lord is a planet in the Midheaven/10th house. If there is no planet in the Midheaven then:
  3. The Lord is a planet in the 11th house.

Second Approach

Planets capable of being the Lord of the Nativity in the second approach are:

  1. The domicile lord of the Ascendant. Or
  2. A planet in the rising sign, and (especially?) in the bounds of the Ascendant. Or
  3. The lord of the Moon. Or
  4. The lord of the Lot of Fortune. Or
  5. A planet that makes a heliacal rising, setting, or retrograde station within 7 days of the birth (if there are multiple then the one that is not under the beams is preferred).
  6. The bound lord of the prenatal lunation.

Porphyry makes an important statement after outlining the second approach to the effect that the Lord of the Nativity is the planet that generally is:

  • Capable of rising out from under the beams of the Sun.
  • Has more familiarity (“dignity”) in its location, through zodiacal rulership.
  • Has the most “power” in relation to the “figure” of the nativity, which probably means being in one of the “advantageous” or “busy” places, which are houses that are more angular.
  • Has the most power in relation to its configuration with the other stars in the chart.

Further Reading

For a translation of the Porphyry passages that these calculations are discussed in see:

  • Porphyry the Philosopher, Introduction to the Tetrabiblos, chapter 30, trans. James Holden, American Federation of Astrologers, Tempe, AZ, 2010.

Watch the Video Version of This Episode

Here is the video version of our episode on the master of the nativity:

Listen to the Audio Version of This Episode

You can either play this episode of the podcast directly from the website or download it as an MP3 to your computer by using the buttons below:


  1. Amy Nicole says

    Wow very extensive and interesting. Thank you both. It also reminded me of the templar’s quest for “knowledge and conversation with your holy guardian angel” etc.. (also random side note, my last name is the Latin version of porphyry: Purpura.) thanks again!

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