Decennials

What are Decennials (Decades)

Decennials (from Lat. decennium — decade) is an ancient method of astrological forecasting described by Hellenistic authors such as Vettius Valens and Julius Firmicus Maternus. The method allows one to divide a person’s life into major periods (chronocrators) in order to determine the planet that will set the main backdrop and events for each specific time span.

Unlike Firdaria, where the order of planets is fixed and depends only on whether the native was born by day or night, in Decennials the order of periods is strictly individual and is built on the basis of a specific natal chart.

How the first ruler is determined

The calculation always begins with finding the most powerful planet in the chart (the luminary), which gains the right to become the first ruler (Chronocrator) and open the life cycle:

• For a diurnal birth, the cycle usually begins with the Sun (if it is well-placed) or with the planet following it in the zodiac.
• For a nocturnal birth, the cycle begins with the Moon (if it is strong) or with the planet following it in the zodiac.
• If the luminary is weakened in the chart (for example, located in a cadent house), the right of the first ruler passes to the planet following it.

Duration of periods (Great Years)

In Decennials, each planet rules a period equal to its “great” or “minor” years, to which months and days are added. The main life cycle (Great Periods) is calculated in years plus a quarter of a year:

• Sun — 10 years and 9 months (129 months)
• Moon — 9 years and 5 months (109 months)
• Saturn — 30 years (360 months)
• Jupiter — 12 years (144 months)
• Mars — 15 years (180 months)
• Venus — 8 years (96 months)
• Mercury — 20 years (240 months)

(Note: the total base cycle of all planets is 109 years).

Order of succession (Transfer of rulership)

After the first planet has completed its term, it transfers rulership to the next planet. The order of planets is determined by their actual position in the natal chart — strictly in the order of the zodiac signs (counterclockwise). For example, if the first period belonged to the Sun in Aries, and the next planet in the zodiac in the chart is Venus in Gemini, then it becomes the ruler of the second period.

Sub-periods

Each Great Period is divided into smaller sub-periods (distributed proportionally in months and days), which are also ruled by planets. The first sub-period always belongs to the ruler of the Great Period, and then rulership of the sub-periods is transferred according to the same scheme — to planets in zodiacal order.

Interpretation

• The major ruler shows the general long-term backdrop of life, the mood and global themes (according to the nature of the planet and the house it rules in the chart).
• The minor ruler (of the sub-period) points to specific events that will occur against this backdrop. The relationship between the major and minor rulers in the natal chart (their aspects and receptions) shows how harmonious or difficult this time span will be.

Implementation in the ZEUS program

In the ancient texts (of Vettius Valens, Julius Firmicus Maternus) there are several discrepancies regarding exactly how to distribute the duration of the Great Periods. The ZEUS program implements the most mathematically coherent and logical version of Hellenistic Decennials, based on strict fractal nesting of cycles.

The calculation of periods in the program uses a three-level system:

1. Level of Great Periods (Chronocrators) At the first level, each ruling planet is allocated an equal period of time — exactly 10 years and 9 months (which equals exactly 129 astrological months). This approach justifies the very name of the method “Decennials” (decades), since each global life stage lasts slightly more than 10 years, regardless of which planet rules it.

2. Level of sub-periods (Months) Within the Great Period (129 months), rulership is transferred to all seven planets in turn (starting with the ruler of the Great Period and then in zodiacal order). At this level, each planet is allocated a number of months exactly equal to its “minor years”:

• Saturn — 30 months
• Moon — 25 months
• Mercury — 20 months
• Sun — 19 months
• Mars — 15 months
• Jupiter — 12 months
• Venus — 8 months

(The sum of the minor years of all seven planets perfectly equals 129 months, completely filling the Great Period of the first level).

3. Level of micro-periods (Days) At the third, deepest level, the months of the sub-period are again divided among all the planets. The ZEUS program implements the algorithm of proportional division of days described by Vettius Valens in his “Anthology.” The number of days each planet receives within a sub-period is calculated strictly proportionally to its “minor years” relative to the total duration of the current sub-period.

Thus, the ZEUS program provides the user with a deep, mathematically verified ancient model of time unfolding, allowing the analysis of periods down to specific days.

The planet from which the cycle begins can be selected from the context menu.

By clicking on a sub-period row, the corresponding sub-sub-period can be seen in the right table.

Hovering over the i icon will display a tooltip with details about the calculation specifics.