Why did the Golden Dawn employ the Placidus System of House? – Part 1

Figure 1. Placidus de Titus, a Olivetan monk, professor of mathematics, physics and astronomy, and astrologer.

The topic of Flying Roll XXIV is “On Horary Astrology”. This Flying Roll was written by Dr Berridge (also called V.H. Frater Resurgum) and focuses on demonstrating the technique of Horary Astrology, although is a very bare form. While reading the “Commentaries of the Golden Dawn Flying Rolls” it was noted that while Horary Astrology traditionally employed the Regiomontanus System of Houses, Dr Berridge used the Placidus System of Houses (1). In many other examples of the Golden Dawn’s use of Astrology, we see the use of the common Placidus System of Houses. So the question is, why did the Golden Dawn stick to this specific System when much of their influence stemmed from authors like William Lilly who specifically favoured the Regiomontanus System of Houses? Furthermore, what are the differences between Placidus and Regiomontanus?

I believe there are two main reasons why the Golden Dawn favoured Placidus over Regiomontanus and other systems. The first is more so accidental in that in the late 19th century, Placidus was the most widely published System of Houses, certainly in the United Kingdom. In his blog post,  astrologer Anthony Lewis describes how British Astrologers in the 17th century deliberately popularized Placidus as they firmly believed it accurately represented the original ideas of 2nd century Hellenistic Astrologer, Claudius Ptolemy (2). Furthermore, the creator of this system, Placidus De Titus (3), systematically had his writings banned by the Catholic Church. Any excuse for the Protestant Church of England to defy the Pope after the reformation! Prior to this, Regiomontanus was the most widespread System of Houses, which is a major reason it would appear in the works of William Lilly (4).

However, the writer of the Flying Roll, Dr Berridge, was probably well aware of the differences between Regiomontanus and Placidus, as he authored several papers on Astrology in the Golden Dawn, including some published in “Astrology of the Golden Dawn” (5). There has to be another reason why Berridge specifically chose this System of Houses over that promoted by William Lilly. In ceremonial magic, the concept of planetary days and hours are used to time rituals. The founders of the Golden Dawn were very much aware of this, gaining much influence from authors such as Cornelius Agrippa (6), or the Keys of Solomon (7). How do planetary hours relate to the Placidus System of Houses? It is actually surprisingly simple.

The ecliptic itself is defined by the apparent anticlockwise motion of the Sun through the twelve signs of the Zodiac over the period of one year from the reference from of an observer on Earth. In reality this is based on the annual motion of the Earth around the Sun. However, over the period of one day the Earth also spins on its axis. From the reference frame of the observer on Earth, the Sun also travels in a clockwise direction across the sky during the day and under the earth during the night. Much like the division of the ecliptic into Twelve sections (the Zodiac), the diurnal motion of the Sun as the Earth revolves sets up a set of 12 areas of the sky called Houses, six below the Earth and six above. On average, the Sun will take two hours to travel through a House, although the individual transit times are heavily based on the observers position on the planet and the time of year.

This is all interesting, but it still does not connect the Placidus System of House to the planetary hours. As the Sun rises in the morning on the eastern horizon (the degree of the Ascendant), it will enter the 12th House, as it rises towards the highest point in the sky, it will pass through the 11th  and 10th House and will reach the Cusp of the 10th House (the MC) when the sun reaches its highest point, See Figure 2. From then it will pass though the 9th, 8th and 7th Houses until it reaches the western horizon (the degree of the Descendant) and sets in the evening. It will continue it path though the rest of the Houses until it reaches the degree of the Ascendant the next morning. What is interesting is that the ingress of the Sun into each House corresponds to a new planetary hour exactly. Each transit of the Sun through a House encompasses exactly two planetary hours, see Figure 3. This might be the main rationale the Golden Dawn authors such as Dr Berridge had for employing the Placidus System of Houses.

Figure 2. (a) Sun’s position in the sky when it rises in the morning entering the 12th House. This motion is clockwise from the reference frame of the observer on Earth. (b) Hypothetical midday when the sun reaches its highest elevation in the sky coinciding the the degree of the MC.
Figure 3. Separation of the Placidus Houses into the planetary Hours. The lines extending from the outer circle represent new planetary hours as the Sun passes through the Houses. Notice how every 2nd planetary hour boundary coincides with a House cusp.

This may seem confusing at the moment but in the next blog posts I will elucidate this further.  In Part 2, I will show the physical difference and the similarities between the Regiomontanus and Placidus System of Houses with some nice pictures.


  1. The Golden Dawn Community. Commentaries on the Golden Dawn Flying Rolls. Dublin. Kerubim Press. 2003, pg. 296.
  2. Ptolemy, Claudius. Tetrabiblos. London, Davis and Dickson. 1822.
  3. The Placidus System of Houses is falsely attributed to Placidus De Titus. Many believe this was the system originally referenced by Claudius Ptolemy including 12th Century Astrologer Ibn Ezra.
  4. Lilly, William. Christian Astrology. London. John Macock. 1659.
  5. Brodie-Innes, John William, Astrology of the Golden Dawn. Edited by Darcy Kuntz. Holmes Publishing Group. Lynnwood, WA. 1996.
  6. Agrippa, Cornelius,. Tyson, Donald., and Freak, James. Three Books of Occult Philosophy. St. Paul, MN, U.S.A: Llewellyn, 1993.
  7. MacGregor Mathers, Samuel, L., The greater Key of Solomon. Chicago. De Laurence. 1914.

Published by Manu Forti's Astrology Blog

The blog of a Hellenistic Astrologer in Ireland. I have a PhD in Physics and have 4 cats :)

Leave a Reply

Fill in your details below or click an icon to log in:

WordPress.com Logo

You are commenting using your WordPress.com account. Log Out /  Change )

Google photo

You are commenting using your Google account. Log Out /  Change )

Twitter picture

You are commenting using your Twitter account. Log Out /  Change )

Facebook photo

You are commenting using your Facebook account. Log Out /  Change )

Connecting to %s

%d bloggers like this: