Source-verification research. The scholarly sourcing, citations, and contested points behind this technique — pure research, with no implementation detail. For the curated summary of what Stellium implements (defaults, the forks it chose, simplifications) and how these sources map to the code, see ../README.md.
The Hellenistic/Classical “Planetary Years” Tables: Verified Values and Source Attribution¶
TL;DR¶
The canonical LEAST/MINOR years (Saturn 30, Jupiter 12, Mars 15, Sun 19, Venus 8, Mercury 20, Moon 25) are firmly attested and near-universal (Valens Anthology I & IV; Firmicus Mathesis II.29); they sum to 129, the basis of Decennials, and are the values consumed by Zodiacal Releasing. The GREATER years (Sun 120, Moon 108, Saturn 57, Jupiter 79, Mars 66, Venus 82, Mercury 76) are also stable, with the five non-luminary values derived as the sum of each planet’s bounds/terms across the zodiac (Saturn 57 + Jupiter 79 + Mars 66 + Venus 82 + Mercury 76 = 360).
MEAN years are the arithmetic average of least and greatest (Saturn 43.5, Jupiter 45.5, Mars 40.5, Sun 69.5, Venus 45, Mercury 48, Moon 66.5); GREATEST/MAXIMUM years are the least stable family, with genuine source disagreement (esp. the Moon: 320 in Lilly, 420 in Bonatti, 520 in Al-Qabisi/Al-Biruni/Ibn Ezra).
The claim that Capricorn’s ZR period of 27 = “one-quarter of the Moon’s greater years” (108/4) and Aquarius’s 30 = “one-quarter of the Sun’s greater years” (120/4) is NOT in Valens and is not endorsed by any major modern commentator. It is an unsupported post-hoc rationalization; the arithmetic is coincidentally correct, but no source in the tradition connects those figures to the ZR sign-periods.
Key Findings¶
1. LEAST / MINOR / LESSER YEARS — CONFIRMED¶
The canonical set is confirmed and effectively invariant across the tradition:
Planet |
Least (minor) years |
|---|---|
Saturn |
30 |
Jupiter |
12 |
Mars |
15 |
Sun |
19 |
Venus |
8 |
Mercury |
20 |
Moon |
25 |
Sum = 129. These are given by Vettius Valens at the end of Anthology Book III and again at the beginning of Book IV; by Firmicus Maternus in the Mathesis (Book II ch. 29, “The Division of the Year”); and are the values Robert Hand and Robert Schmidt (Project Hindsight, Valens Book IV introduction) discuss as having a genuine astronomical basis. Curtis Manwaring (astrology-x-files.com, “Zodiacal Aphesis”) gives them identically and states the rationale explicitly: “The minor period lengths are: Sun = 19, Moon = 25, Hermes = 20, Aphrodite = 8, Ares = 15, Zeus = 12, Kronos = 30… the Moon takes 25 Egyptian years to return to the same degree that it was in with relation to the Sun. Venus takes 8 years to recur with the Sun.”
They correspond to synodic recurrence cycles with the Sun. The Sun’s 19 is the Metonic cycle; per Encyclopædia Britannica, this is “a period of 19 years in which there are 235 lunations, or synodic months, after which the Moon’s phases recur on the same days of the solar year” (235 synodic months = 6,939 days 16.5 hrs vs. 19 solar years = 6,939 days 14.5 hrs) — the frequently-cited “254” figure counts sidereal months (19 + 235). Moon 25 = 309 lunations ≈ 25 Egyptian years; Mercury 20 = 63 Mercury–Sun synods ≈ 20 years; Venus 8 = 5 synods ≈ 8 years; Mars 15, Jupiter 12, Saturn 30 = synodic/sidereal returns. No major source gives a different minor-years set for the seven planets. (The one apparent “exception” is not a planet but a sign — Capricorn = 27 in Zodiacal Releasing; see §5.)
2. GREATER YEARS — CONFIRMED, with documented conceptual origin¶
Planet |
Greater years |
|---|---|
Sun |
120 |
Moon |
108 |
Saturn |
57 |
Jupiter |
79 |
Mars |
66 |
Venus |
82 |
Mercury |
76 |
The five non-luminary greater years are the sum of the degrees of each planet’s bounds/terms across all twelve signs (Egyptian/Ptolemaic terms). Verbatim from Deborah Houlding’s Skyscript glossary entry “Great years (of the planets)” (drawn from her Annotated Lilly, footnote 154, pp. 58–59): “The Great (or Greater) years… show the total number of terms that each planet rules throughout the signs (see Ptolemy, Tetrabiblos I.20); i.e., Saturn 57 + Jupiter 79 + Mars 66 + Venus 82 + Mercury 76 = 360.” Because Venus (quick benefic) rules the most terms and Saturn (slow malefic) the fewest, the figures encode planetary speed and benefic quality.
Sun greater years = 120; ¼ of 120 = 30. CONFIRMED. The Sun’s 120 does not come from terms (luminaries don’t rule terms in this scheme); it is explained as the greatest solar semi-arc (~120° within the inhabited latitudes, ~49°N) and coincides with the 120-year total of the Vimśottarī daśā. Per the Bṛhat Parāśara Horā Śāstra (ch. 46), Vimśottarī “spans 120 years,” summing Ketu 7, Venus 20, Sun 6, Moon 10, Mars 7, Rahu 18, Jupiter 16, Saturn 19, Mercury 17 = 120.
Moon greater years = 108; ¼ of 108 = 27. CONFIRMED as arithmetic. The Moon’s 108 is explained as the Sun’s 120° semi-arc minus the ~12° the Moon must be from the Sun to be visible (120 − 12 = 108). 108 is also 27 lunar mansions × 4 padas.
These values are consistent across Valens, Firmicus, the medieval Perso-Arabic tradition, and modern reference tables. The widely reproduced De Vore Encyclopedia of Astrology table gives exactly Saturn 57, Jupiter 79, Mars 66, Sun 120, Venus 82, Mercury 76, Moon 108. I found no primary source giving materially different greater-years values for the seven.
3. MEAN / MIDDLE YEARS — the average of least and greatest¶
Planet |
Mean years |
Check: (least + greatest)/2 |
|---|---|---|
Saturn |
43.5 |
(30+57)/2 |
Jupiter |
45.5 |
(12+79)/2 |
Mars |
40.5 |
(15+66)/2 |
Sun |
69.5 |
(19+120)/2 |
Venus |
45 |
(8+82)/2 |
Mercury |
48 |
(20+76)/2 |
Moon |
66.5 |
(25+108)/2 |
The mean years are defined and computed as the arithmetic average of the least and greatest years (Skyscript/Houlding), confirmed against the alcocoden “Table of Years” reproduced in the length-of-life literature. Some popularized tables round the luminaries (e.g., Sun 69, Moon 66); the precise half-integer values (69.5, 66.5) are the ones used in the alcocoden tables.
4. GREATEST / MAXIMUM YEARS — the least stable family; genuine disagreement¶
Two distinct traditions exist, and they conflict. The widely reproduced De Vore Encyclopedia of Astrology table gives:
Planet |
Greatest (De Vore table) |
|---|---|
Saturn |
465 |
Jupiter |
428 |
Mars |
264 |
Sun |
1460 |
Venus |
151 |
Mercury |
450 |
Moon |
320 |
The astronomically-reconstructed set (Houlding/Skyscript, following Neugebauer, A History of Ancient Mathematical Astronomy III p. 605 ff., and Ptolemy Almagest IX.3), based on sidereal period × “period number,” gives materially different superior/inferior values:
Planet |
Greatest (astronomical) |
Basis |
|---|---|---|
Saturn |
265 |
9 × sidereal period |
Jupiter |
427 |
36 × sidereal |
Mars |
284 |
period relation |
Sun |
1461 |
days in 4 yrs (Sothic/quadrennium) |
Venus |
1151 |
720 × synodic |
Mercury |
461 |
period relation |
Moon |
520 |
three eclipse periods |
The Moon’s greatest year is explicitly the most contested figure. Per Houlding: Antiochus and Rhetorius made it 25 (which clashes with the least-year 25); later authors — Al-Qabisi, Al-Biruni, and Ibn Ezra — made it 520; Bonatti records 420 (likely a transmission error); William Lilly records 320. This is the clearest example of a value that cannot be reduced to a single figure. The greatest years were used chiefly for mundane/dynastic timespans, not natal work.
5. Zodiacal Releasing sign-periods and the Capricorn = 27 problem¶
Zodiacal Releasing (Valens Anthology Book IV, chs. 4–10) assigns each sign the minor years of its domicile ruler:
Aries 15, Taurus 8, Gemini 20, Cancer 25, Leo 19, Virgo 20, Libra 8, Scorpio 15, Sagittarius 12, Capricorn 27, Aquarius 30, Pisces 12.
The technique’s name reflects Greek aphesis (“releasing”); per Chris Brennan (The Astrology Podcast, Ep. 192): “aphesis, which means to release something… this was Robert Schmidt’s translation, and he defends the translation and talks about it in the introduction to his original translation of Vettius Valens… It’s actually 1996.”
Saturn rules both Aquarius and Capricorn. Aquarius correctly receives Saturn’s full 30; Capricorn is the lone exception, reduced to 27.
On the specific claim to verify/refute — that “Capricorn 27 = ¼ of the Moon’s greater years (108/4)” and “Aquarius 30 = ¼ of the Sun’s greater years (120/4)”:
It is NOT stated by Valens. Valens assigns the number without explaining the anomaly; there is no explanatory sentence in Book IV. This silence is confirmed by every practitioner-scholar who works from the text (Brennan; Patrick Watson, who bluntly calls the Capricorn/Aquarius difference unexplained; and the Mark Riley translation).
It is NOT a documented reconstruction by Schmidt, Brennan, Manwaring, or George. No major modern commentator proposes or endorses the “quarter of greater years” formula.
It is best characterized as unsupported folk-etymology. The arithmetic (108÷4=27; 120÷4=30) is coincidentally correct — the Moon’s and Sun’s greater years genuinely are 108 and 120 — but no source connects those figures to the ZR sign-periods.
The genuine, sourced symbolic association for 27 in the modern literature is Curtis Manwaring’s essay “The Mystery of 27” (astrology-x-files.com/x-files/mysteryof27.html, citing Valens Anthology Book I p. 30 and Book IV p. 11, Schmidt trans., 1997), which ties 27 to the 27 lunar mansions/nakshatras, not to 108÷4. Most sources simply describe Capricorn’s 27 as an inherited “reduction” whose original rationale is not preserved. Structural observations exist (e.g., Scorpio 15 + Sagittarius 12 = 27; Pisces 12 + Aries 15 = 27), but these are noted as coincidence, not origin.
Loosing of the bond in ZR occurs only in signs whose periods exceed the ~17.5-year sub-period cycle — i.e., signs ruled by the Sun, Moon, Mercury, and Saturn (Leo 19, Cancer 25, Gemini/Virgo 20, Capricorn 27, Aquarius 30).
Details¶
Uses of each “years” family, with sources¶
Zodiacal Releasing → LEAST (minor) years. ZR Level 1 periods use the minor years as years (360-day years), L2 as months, L3 as days, L4 as 1/12 of days. Source: Valens Anthology Book IV; recovered and named by Robert Schmidt (Project Hindsight, translation 1996); popularized by Chris Brennan (The Mountain Astrologer, Apr/May 2012, “Annual Profections, Lots, and Zodiacal Releasing”; and Hellenistic Astrology: The Study of Fate and Fortune, 2017). Standard software: Curtis Manwaring’s Delphic Oracle.
Length-of-life / alcocoden (aphetic) technique → GREATER (angular), MEAN (succedent), LEAST (cadent). The alcocoden (Arabic al-kadhkhudāh, “giver of years”) grants years by condition. The mainstream rule (Bonatti; Bernadette Brady, The Hyleg and Alcoccoden; the standard alcocoden Table of Years): angular + dignified → greater years; succedent → middle/mean years; cadent → least years. Aspects then modify: benefics (Jupiter, Venus) in aspect add their least years; Mercury (if strong, sextile/trine, free of the infortunes) adds its least years; the Sun/Moon in sextile/trine add their least years; malefics (Saturn, Mars) by conjunction/opposition/square subtract their least years; the Sun/Moon by conjunction/square/opposition subtract their lesser years; the alcocoden in fall or retrograde loses half its years; combust, it gives months or days instead of years (per Omar of Tiberias / the rules “according to Others” in the length-of-life literature).
Ptolemy (Tetrabiblos III.10–11) treats only the apheta/prorogator and the anareta, with no separate governor/alcocoden and no years-table — he uses primary directions of the prorogator to the anareta, with benefic aspects adding and malefic aspects subtracting time. The years-table apparatus is Perso-Arabic (Māshā’allāh, Sahl, Abū Ma’shar, Al-Qabisi) synthesized into Bonatti and Lilly. NOTE A GENUINE VARIANT: some modern sources invert the mapping (minor when angular, greater when cadent). This appears to be a minority/erroneous reading — the dominant traditional rule is angular = greater.
Firdaria (Persian time-lord system) → its own period set, DISTINCT from the least years. The firdaria periods, verbatim from Abu Ma’shar (trans. Benjamin Dykes, Persian Nativities): “The firdar of the Sun, then, is 10 years; of Aphrodite, 8; of Hermes, 13; of the Moon, 9; of Kronos, 11; of Zeus, 12; of Ares, 7; of the Ascending Node, 3; of the Descending Node, 2 – altogether, they are 75.” These are NOT the least years (e.g., firdaria Sun 10 vs. least-years Sun 19; firdaria Moon 9 vs. 25; firdaria Saturn 11 vs. 30). Day charts begin with the Sun in descending Chaldean order (Sun 10, Venus 8, Mercury 13, Moon 9, Saturn 11, Jupiter 12, Mars 7, then North Node 3, South Node 2); night charts begin with the Moon (Moon 9, Saturn 11, Jupiter 12, Mars 7, Sun 10, Venus 8, Mercury 13, then the nodes). Sources: transmitted via Abu Ma’shar and Al-Qabisi, used by Bonatti (Liber Astronomiae) and Lilly; modern: Benjamin Dykes (Persian Nativities), Christopher LaFond. The placement of the nodes varies between authors (Abu Ma’shar/Schoener place them at the end of the sequence; some later handlings reorder or, in the nocturnal case, position them differently). Each major period subdivides into seven sub-periods in Chaldean order beginning with the major-period ruler.
Decennials → LEAST years (as months), summing to 129. Each planet rules 10 years 9 months (= 129 months), because the seven least years sum to 129 and 129 ÷ 12 = 10.75 years. The sequence begins from the sect light (Sun by day, Moon by night), then proceeds by the planets encountered in zodiacal order. Each 129-month period subdivides into seven sub-periods whose lengths are the minor years counted as months (Saturn 30 months, Jupiter 12, Mars 15, Sun 19, Venus 8, Mercury 20, Moon 25). Sources: Valens Anthology Book IV; Hephaistio of Thebes Apotelesmatika Book II (Schmidt trans., p. 83, quoting “the ancient Egyptians”); Firmicus Mathesis Book II.29 (the “planetary days”) and the periods material; attributed in antiquity to Critodemus (2nd c. BCE).
Related chronocrator/planetary-period techniques. Valens’ “planetary days” (Book IV / Firmicus II.29): the minor years and their doubles/halves/thirds define numbers of days summing to ~365.5, used to distribute the profection year among planets. Valens’ “Quarters,” the “distributions/transmissions” (Book IV chs. 17–25), and the ascensional-times timing (Book VII) also consume the minor years and their fractions.
Modern reference works — what each contains¶
Chris Brennan, Hellenistic Astrology: The Study of Fate and Fortune (2017): presents the minor years and their use (ZR; activation of configurations by ordinal year — e.g., Mars at 15 activates in the 15th year, age 14–15) and a length-of-life overview (pp. 507–510). It centers the minor years rather than a full four-column table.
Demetra George, Ancient Astrology in Theory and Practice (Vol. I, 2019): ch. 26, “The Synodic Cycle & the Minor Years of the Planets,” covers the minor years and their synodic basis; ch. 34 covers ZR from the Lot of Fortune.
Benjamin Dykes: translations of Persian Nativities (firdaria, alcocoden), Bonatti’s Book of Astronomy / Liber Astronomiae (greater/mean/least years for length of life), and Firmicus’s Mathesis.
Deborah Houlding / skyscript.co.uk: the glossary entries “Least years,” “Mean years,” “Great years,” and “Greatest years” (from her Annotated Lilly, footnote 154, pp. 58–59) are the most convenient sourced tables, including the terms-sum derivation and the greatest-years variants.
Curtis Manwaring / astrology-x-files.com: ZR and firdaria material; the “27 = lunar mansions” note (“The Mystery of 27”); the Delphic Oracle software.
What would revise these findings¶
If a direct, verbatim Valens Book IV passage explaining Capricorn’s 27 were located (none is currently preserved), or if a named commentator’s published derivation of the “¼ of greater years” rule surfaced, §5 would change — at present the derivation is unsupported folk-etymology.
If Dykes’s Bonatti or a primary Perso-Arabic text were consulted directly, the greatest-years variants could be reconciled against it more firmly.
The reliability tiers stand: least / greater / mean are near-universal; greatest is genuinely unsettled and no single value can be treated as authoritative (see Caveats).
Caveats¶
Greatest years are genuinely unsettled. Numbers cited for the Moon (25 / 320 / 420 / 520) and for the superior/inferior planets differ between the “De Vore table” tradition and the astronomical reconstruction (Neugebauer/Houlding). Both are reported above; neither can be treated as the single correct value.
The alcocoden angular/cadent → greater/least mapping has a documented inversion in some modern sources. The dominant traditional rule is angular = greater.
Ptolemy does not supply a planetary-years table for length of life; his method (Tetrabiblos III.10–11) is directional (apheta to anareta). The four-column years-table apparatus is Perso-Arabic/medieval. Attributing the full table to Ptolemy directly would be inaccurate — his contribution is the terms whose sums yield the greater years, plus the aphetic framework.
Mean-year rounding varies (Sun 69 vs. 69.5; Moon 66 vs. 66.5) across popular tables; the half-integer values are the ones used in the alcocoden tables.
The Metonic cycle is properly 235 synodic months (Britannica); the “254” often quoted counts sidereal months. Several supporting values here were corroborated through secondary reproductions of the Riley translation and the De Vore encyclopedia rather than the printed critical editions; the exact Valens Book III/IV and Firmicus II.29 passages are best confirmed against the printed Riley (2010/2022) and Kroll critical editions.