Decennials – Ancient Timing Technique

I have discovered, tested, and put to use the following distribution, which had been discarded casually,
even blindly, because the explanation of it had been puzzling. I append it now so that lovers of beauty may
make their nature divine, travelling through many paths to one power of forecasting. They may expect to
meet in one place after travelling many straight, as well as many rough, roads.
(Vettius Valens – Abthologies, Book VI, Riley trans., p.117)

I have found this technique used at several places and these places (according to my current position of material I’ve read) are:
– Vettius Valens – book VI of Anthology.
– Hephaistio of Thebes – Apothelesmatics, Book II, Chapter 29.
– Firmicus Maternis – Mathesis, Chapter 33.
– The now famous analysis of the chart of the Italian nobleman Alfonso D’este from an unknown Italian astrologer from 16th century.

Some say that the medieval title of this technique as “Decennials” is a misleading and wrong, but I’ve found it “handy” for use in lack of a better name. Decennial means “recurring in ten years”, which is not the precise timing because the technique uses a period of 10 years and 9 months and not 10 exact!

What is the logic behind the 10.9 division?
The sum of the lesser years of the planets is 129 years total. The sum of 10 years and 9 months is 129 months. It is like a microscopic mirror of the cycle of the lesser years of the planets.

The first planet in the cycle starts from the beginning of life till 10 years and 9 months.
Here is a simple table:
1. From 0 years, o months to 10 years, 9 months.
2. From 10 years, 9 months, to 21 years, 6 months.
3. From 21,6 to 32,3.
4. From 32,3 to 43.
5. From 43 to 53, 9.
6. From 53,9 to 64,6.
7. From 64,6 to 75,3

Some of the ancient Egyptians, having already added together the periods of the 7 stars, which extend to 10 years and 9 months, beginning from the primary light of the sect, divided (this number) among the stars successively in zodiacal order, giving to each planet its own period; and furthermore also making a proportionate subdivision of each period into shorter times, they likewise gave them to each of the planets in order, (starting) from the time-lord”
(Hephaistio of thebes – Apothelesmatics, Book II, Schmidt trans., p.83)

Places Conducive to Business

However, the problem arises in choosing from which light to start the chronocratorship. All sources seems to agree that we should start from the light of the sect, but if it is “declining and unconnected to the Horoskopos” Hephaistio advises us to use the other light, and if this is also in bad shape, then Valens advises us to use the first planet (in good shape?) after the Horoskopos in zodiacal order.

Here we must apply the doctrine of the busy and non-busy places (operative and non-operative).
The places conducive to business, or in Greek “Chrematisticos” (which means “profit) are places where the planet is said to have operative strength. “Achrematisticos” are non-profitable places, or places non-conducive to business.

According to Nechepso, Achrematistikos are only the cadent places.

But according to the system of Dorotheus, non-profitable places are only the places that don’t regard the ascendant (2, 6, 8, 12) and for some reasons the 3rd which is the only place of these which regards the ascendant. Hephaistio seems to use Dorotheus’ system because he says “if the planet is declining and unconnected to the Horoskopos”.

The question that arises is whether the Sun in 9th in the system of Nechepso would be counted as “Achrematistikos” when we know that it is in its joy; and Moon in 3rd in both systems, when we know that the third is her joy. I don’t think that the lights are achrematistikos in those places.

However, the unknown Italian astrologer, who probably follows Firmicus – who BTW didn’t gave strict rules for which planet to use and when to use – in his analysis of the chart of Alfonso D’este, starts with Sun which is in the 8th place, which is a place conducive to business according to Nechepso, but not for Dorotheus.

In my own practice I’ve found that in some cases the 8th place apheta is operative for using it in this technique, but it all depends. This planet may be attacked and made unfortunate in different ways then just being in place conducive or non-conducive to business.

For example, Valens gives us an example of a night birth where Moon in Pisces on IC was operative to be an apheta. Valens says that this is so because she is on IC, in feminine sign and in a triangle of the sect member (Mars rules the watery triplicity in a night charts), and is “appropriately situated”.

As we can see, Valens here does not investigate Moon’s place only, but the position in zoidia and triangle. But my mind full of questions again and again goes back to the unknown Italian astrologer and I’m asking myself why he used Sun as apheta.

An introduction to this astrologer you can read on these two links:

The second link is in Italian, but the first link is very good introduction in English from Margherita Fiorello. I advise you first to read her article, and then if you know Italian or use Google Translate, try to read the Italian article.

Back to the Italian astrologer. I think he had no other option than the Sun.
If he discarded the Sun because of the placement in the 8th, then get to the Moon, he probably saw as we see that the Moon is in 12th house, place achrematistikos in both systems. Then he probably looked at the first planet after the ascendant, and saw Mars in Sagittarius, malefic contrary to the sect in favor and a planet which is not suitable for being apheta. Jupiter and Saturn are in bad zodiacal shape, Mercury and Venus are also in 8th place, so the Sun in the zoidia of a sect member, in 8th, and first option by day, probably was the best candidate of this magnificent astrologer, knowing that some astrologers in the past has used the 8th place as chrematistikos.
And he did great job of predicting the life of Alfonso D’este with great precision.

I know that many people would like to have strict rules in choosing the apheta, but I don’t think there can be such rules. Sometimes a Light in angular house would not be fit to be apheta. It all depends on the circumstances of the chart, and experienced astrologer would use his experience and knowledgeable intuition to decide from which star to start the distribution.


Rulership of the Decennials are then subdivided into the rulership by months, i.e. days.
The distribution of the months is according to the lesser years of the planets minimized in to months instead of years. So, Saturn would rule 30 months, Jupiter 12, Mars, 15, Sun 19, Venus 8, Mercury 20, and Moon 25.

The order of the planet would not be like the one I gave here in the tables (except accidentally), but will go to the zodiacal order of the placement of planets in the particular chart. Saturn when rules by monthly decennials, will always give the first distribution of days to himself, and then would give the following days to the planet next in zodiacal order and etc.

Distribution of days is less proportional and there exist two systems, the one which Hephaistio gives and the one which Valens gives. Valens’ system seems more precise because it divides the months of the planet which rules up to the minute precisely. Hephaistio’s system adds more days to the distribution which exceeds the monthly rulership of the planet in question.

I will present here the both systems in tables, so you decide which you will use in your practice.
When Saturn rules the Decennials, the monthly rulership then goes in the following order:

  • According to Hephaistio:                                              According to Valens:
    Saturn gives to itself 210 days.                                209 days, 6 1/4 hours.
    Jupiter 84 days                                                                83 days, 17 1/3 hours
    Mars 105 days                                                                 104 days, 15 2/3 hours
    Sun 133 days                                                                    132 days, 13 5/12 hours.
    Venus 56 days                                                                 55 days, 19 1/2 hours.
    Mercury 150 days                                                          139 days, 12 2/3 hours
    Moon 175 days.                                                              174 days, 10 hours.

Note: Hephaistio’s system gives total of 913 days, which is 13 days more than Saturn’s actual rulership of 900 days (30 months multiplied by 30 days).

Naming of the Periods

Some use the names “General time lord” and “Specific time lord” to designate the overall ruler of 10.9 period (general) and the ruler of the months (specific).
Other astrologers use the names 1st, 2nd and 3rd level to make a difference in rulership assumed.

360 year or Conventional Year?

With the advancement of astronomical observations and calculation tools, it is well established at present day that the actual year is 365.2421897 days in length.

Egyptians, Mayans and Babylonians (to name a few) had in use a calendar of a year 360 days long. However, they were still aware of the fact that this was not an actual length, and the astronomers of those days reported that the actual length of the solar cycle is 365 ¼ days.

There is interesting myth on the increasing of the length of the year involving different Egyptian gods:
A long time ago, Re, who was god of the sun, ruled the earth. During this time, he heard of a prophecy that Nut, the sky goddess, would give birth to a son who would depose him. Therefore Re cast a spell to the effect that Nut could not give birth on any day of the year, which was then itself composed of precisely 360 days. To help Nut to counter this spell, the wisdom god Thoth devised a plan. Thoth went to the Moon god Khonsu and asked that he play a game known as Senet, requesting that they play for the very light of the moon itself. Feeling confident and that he would win, Khonsu agreed. However, in the course of playing he lost the game several times in succession, such that Thoth ended up winning from the moon a substantial measure of its light, equal to about five days. With this in hand, Thoth then took this extra time, and gave it to Nut. In doing so this had the effect of increasing the earth’s number of days per year, allowing Nut to give birth to a succession of children; one upon each of the extra 5 days that were added to the original 360. And as for the moon, losing its light had quite an effect upon it, for it became weaker and smaller in the sky. Being forced to hide itself periodically to recuperate; it could only show itself fully for a short period of time before having to disappear to regain its strength.


Egyptian calendar was based on a lunar cycle of 12 months grouped in three seasons of 4 months each. They based the system on the flooding (rise and fall) of the river Nile which begins to rise somewhere in the end of June. But this was not a precise measurement because it happened in period of 80 days, so the experienced astronomers of those days noticed that the Nile’s rising coincide with the heliacal rising of the brightest star in the sky: Sirius.

The rising of Sirius was somewhere near the date of 21th of June in the constellation of Canis Major. The Egyptians called this date “The Opening of the Year”. But because rising of Sirius is a stellar event which occurs every 365 ¼ days, and the Egyptian calendar was based upon the lunar cycle, the dates did not matched because the lunar cycle ended after 354 days – 11 days before the solar year. To correct this, the Egyptians add an extra month to create a “Great Year” of 384 days in every 2 or 3 years.

In 238 BCE Ptolomy III add an extra (epagomenal) month of 5 intercalary days, or 6th “leap” day on every 4th year to match the solar cycle.

In the calendar most in use today (Gregorian calendar), those intercalary days are distributed in certain months (with 31 days instead of 30) throughout the year. Every 4th year is a leap year where February has 29 instead of 28 days to add that 6th intercalary or a leap day.

There are some scholars who believe today that once the actual year was of 360 days of length indeed. It is a well-known astronomical phenomenon today that the change in speed of the axial rotation of Earth, directly affects the orbital distance between the earth and moon.

However, for our purpose of learning “the way” of the ancient astrological masters, I propose to use their method of 360 days a year, which of course, will require converting.


Converting the dates

This will require having calculator in your hand or in your computer and access to this webpage: where you can calculate how many days are in between two dates in 365 days year.

Valens uses 360-day system for calculating the distribution of days and cycles, but a 365 ¼ days for calculating the native’s years.

129 months multiplied with 30 days equals 3870 days in total.
3870 divided by 365.25 (365 ¼ days) equals 10.595.
To convert these 595 in days, you need to further multiply these 595 with 365.25 to get around 218 days. So, a decennial reulership would be 10 years and 218 days in total.

But let’s try a little bit easier method by using this web tool:

This is a date calculator where you add a number of days from a certain date, in order to find the resulting date in the 365 days system.

Let’s find the decennial distributions of this chart:


The person is born 23 January 1984. For the sake of the example let’s assume that Sun is apheta.
We enter the date in the first column of the web tool and in the column bellow under the group of Days (be sure to check ADD instead of subtract) add 3870 days. The web tool will calculate the date 3870 days from 23 January 1984. 3870 as we said are 129 months of 30 days each multiplied. We came to the date of 28 August 1994. Sun will rule the Decennials by general period from 23 January 1984 to 28 August 1994.

Next we put the new date (28 august 1994) in the first column and calculate again 3870 days from that date, to see to which date will rule the Moon by general period and etc.

To find the months rulership you will first calculate with your calculator how many days has the particular monthly rulership. For example, Moon rules 25 months which multiplied with 30 days month gives total of 750 days. To find to which date Moon rules the specific (monthly) times you only add the number (750) in the days column in the web tool I refer above.
In our example, Moon would rule from 28 August 1994 till 16 September 1996, which is total of 750 days, or 25 months of 30 days each month.


Let’s try this technique with an example.

I have been in doubt whether to use Sun as apheta or Moon in this nativity (see the chart above).
Sun is in 8th so according to Dorotheus’ system non-operative, but according to the system of Nechepso, place conducive to business.
Hephaistio would probably use Moon. But since Sun is in the trigon of its own sect buddy (Saturn), I will try to use it as apheta and we will see where would lead us.

The date in question is 30 of June, when native was 28 years and 159 days old.

Open the two web applications: date to date calculator and date calculator.
Go to date calculator add the birth date and in the column named “days” add 3870 days. This brings us to 28 August 1994. Sun will rule from birthdate, till 28 August 1984.

Then Sun transmits to Moon. To find the exact period of rulership, now enter the new date and add 3870 days. This brings us to 2 April 2005. Then Moon transmits to Mars who rules from 2 April 2005 to 6 November 2015.

Because this exceeds the date in question, we now need to calculate the specific rulership.

Mars would distribute to himself 15 months, this is 450 days. We add 450 days in the column named “days” of the date calculator. This leads us to 26 June 2006. Then Mars distributes to Saturn 30 months, or 900 days. This leads us to 12 December 2008. Saturn will rule the specific period till 12 December 2008. Then Mars distributes to Venus which rules 8 months or 240 days.
This leads us to 9 August 2009. Then rules Jupiter for 12 months or 360 days. This leads us to 4 August 2010. The next specific ruelrship goes to Mercury for 20 months or 600 days. This leads us to 26 March 2012. On 26 March 2012 the specific rulership goes to the Sun which rules 19 months or 570 days. This exceeds the date in question, so we should now count the daily rulership. Sun would distribute to himself (refer to the tables above) 84 days according to Valens’ table (I round 84 because of the 22 hours, and try to compensate later).
From 26 March, 84 days leads us to 18 June 2012. Next rules Moon for 110 days, and here we found the daily ruler.

So the rulership goes like this:
Mars received the distribution from Moon, Sun received the distribution from Mars, and Moon receives from Sun.

We can see that the times are troublesome because the general ruler is the contrary to sect in favor malefic – Mars. Mars receives from Moon which is the ruler of the nativity, and Mars transmits to Sun. Hephaistio says that Mars distributing to Sun by day brings “dangers and plaints on account of public affairs.

The event that happened was very troublesome for the native, and he was in danger for losing his life. Also, dangerous problems with coworkers arise and this brought him public infamy.

Sun is in the 8th but is goaded toward action in the 7th angle.

For the Sun transmitting to Moon in diurnal nativity, Hephaistio says that it is not good, because it brings jealousies and loses.

Further investigation needs to be made in the usage of Decennials. I’m planning to investigate their timing on more life events to compare the results and I hope I will be able to post them in future posts. I have used Firdaria in the past and I have good results with it. But the technique of Decennials intrigued me so many times, and I just can’t ignore it.
I hope that this short introduction to the Decennials will spark the enthusiasm in your astrology soul, to investigate furthermore in this direction and to use this very ancient timing technique.

Vettius Valens – Anthologies, translated by Mark T. Riley.
Vettius Valens – Anthology, book VI, translated by Robert Schmidt (The Golden Hind Press, 1997).
Hephaistio of Thebes – Apotelesmatics, Book II, translated by Robert Schmidt (The Golden Hind Press, 1998).
Joseph Crane – Astrological Roots: The Hellenistic Legacy (Published by The Wessex Astrologer Ltd, 2007)


The charts are calculated in free Morinus software.

© Beyond The Heaven, Sep. 2012

4 thoughts on “Decennials – Ancient Timing Technique

    • Hi Trojan.

      Yes, in Dorotheus’ system apheta in 8th is not conducive to business. But in the system of Nechepso, as I’ve explained above, it is. Therefore I decided “for the sake of the example” to use 8th place apheta as the unknown Italian astrologer did.
      I will try the same chart with Moon as apheta though, in some future post, if time allows.

      • Hvala, Ile, za odgovor. Jaz imam rajši ta sistem kot firdarijo. Ali si prevedel termin Deccenials v makedonski jezik?
        Lep pozdrav iz Slovenije,

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