Last updated: August 12, 2026
Perso-Arabic Astrology
Free Hyleg Calculator
Apply 'Umar al-Tabari's hyleg procedure, with degree based Porphyry places, sect and prenatal phase order, and required dignity lord testimony. The method can return no qualified hyleg.
What is the hyleg in astrology?
The hyleg is the life indicator or releaser in a family of historical length of life procedures. Candidate points include the Sun, Moon, Ascendant, Lot of Fortune, and the prenatal lunation (the New or Full Moon before birth). Each author supplies a distinct order and set of qualifying conditions.
This calculator implements 'Umar al-Tabari's procedure in Three Books on Nativities I.4, translated by Benjamin Dykes in Persian Nativities II (2010). It preserves 'Umar's sect and prenatal phase order, degree place tests, and mandatory dignity lord testimony. It does not combine those instructions with Ptolemy, Valens, or a modern dignity score.
The calculation may end without a qualified hyleg. That indeterminate state preserves the method when every point fails its place or witness requirement. It also makes author differences visible, since another procedure can reach another result from the same chart.
Hyleg comes through Middle Persian and Arabic transmission and is functionally related to the Greek aphetes, or releaser. The label on this page is historical terminology. The result does not measure life expectancy, medical health, or a date of death.
How to find the hyleg
This calculator follows 'Umar's sequence as a set of eligibility tests. It selects the first point that passes its place and testimony requirements. It does not add candidate scores or force a fallback.
Step 1: Determine sect
In a day chart the Sun is tested first, followed by the Moon. In a night chart 'Umar begins with the Moon, and this calculator runs that opening rule. The same chapter reports a night-Sun opinion, credited to Ptolemy and Dorotheus, that admits the Sun below the earth in the places opposite the day-Sun places; the result names that branch and keeps it outside the calculation. Sect also determines the triplicity lord used in the witness test. The sect tool derives sect from your birth data.
Step 2: Apply the prenatal phase order
If the lights fail, a prenatal Full Moon puts Fortune before the Ascendant. A prenatal New Moon puts the Ascendant before Fortune. The prenatal lunation itself is the final candidate. A missing lunation is reported as unavailable rather than inferred.
Step 3: Locate each candidate by degree
The tool computes Porphyry quadrant cusps from the natal Ascendant and Midheaven, then places the exact candidate degree between those cusps. 'Umar gives candidate specific rules. The day Sun has its own named places, the Moon has an angular or succedent rule with a feminine sign condition, Fortune and the prenatal lunation require an angle or succedent, and the Ascendant occupies its own place.
Step 4: Require dignity lord testimony
The domicile, bound, exaltation, or sect triplicity lord of the candidate's degree must see it by whole sign conjunction, sextile, square, trine, or opposition. A dignity claim without testimony does not qualify the point. The result names every witnessing lord.
Step 5: Preserve an indeterminate result
The first candidate that passes both conditions becomes the hyleg. If none passes, the result remains indeterminate under 'Umar's method. The table keeps every rejection reason visible for review.
The five candidate points
'Umar tests up to five points through candidate specific place and testimony rules. Some points are skipped by sect or missing source data, and all available points can fail. These entries describe the historical symbolism of a qualified result.
The Sun
Diurnal light, first candidate by day
In a day chart, 'Umar checks the Sun first. It qualifies in the Ascendant, Midheaven, or 11th place, and may also qualify in the 8th or 9th when it occupies a masculine sign. One of its domicile, bound, exaltation, or triplicity lords must witness it.
When the Sun is your hyleg, read the vitality thread through solar topics: agency, visibility, recognition, and the condition of the natal Sun by sign, house, and aspect. Read it as a symbolic emphasis rather than a health verdict.
The Moon
Nocturnal light, first candidate by night
In a night chart, 'Umar begins with the Moon. By day, he tests it after the Sun. His opening rule places it in an angle or a succedent in a feminine sign, with testimony from one of the same four dignity lords.
When the Moon is your hyleg, weigh vitality through lunar topics: cycles, appetite, rest, care, and the condition of the natal Moon. Lunations can be useful timing context, though they are not medical indicators.
The Ascendant
Phase ordered, with testimony required
When the lights fail, the prenatal phase controls the next step. A conjunctional birth puts the Ascendant before Fortune. A preventional birth tests Fortune first. The rising degree still needs a dignity lord to witness it. The procedure excludes an automatic fallback.
An Ascendant hyleg keeps the reading grounded in embodiment: the rising sign, its ruler, temperament, and the way the native meets the world. Look to the ruler's own condition for the detail.
The Lot of Fortune
First after the lights for a preventional birth
The Lot of Fortune is a calculated point, the arc from Sun to Moon projected from the Ascendant and reversed by sect at night. In this procedure it must occupy an angular or succedent degree region and receive dignity lord testimony.
When Fortune is your hyleg, compare its sign, house, and ruler with the chart's livelihood and physical themes. The Lot of Fortune calculator shows the full computation.
The Prenatal Syzygy
The final candidate in this procedure
The prenatal syzygy is the New or Full Moon immediately before birth, tested after the lights, Fortune, and the Ascendant have failed. It must be angular or succedent and witnessed by a qualified dignity lord.
When the syzygy qualifies, the reading tends to center on inherited context and the pre-birth sky. It rewards synthesis with the rest of the nativity rather than a reading on its own. The prenatal syzygy calculator returns its degree.
A note on length-of-life predictions
Classical astrologers used the hyleg in length-of-life calculations with a technique that combined the alcocoden's planetary years and primary directions to anaretic (destroying) degrees. Bonatti preserves a later Latin reception, and Lilly carries related material into seventeenth century English astrology.
Modern traditional astrologers debate these techniques heavily. The candidate lists and qualifying rules diverge sharply between authors, and the later medieval treatments lean hard on planetary years. A missed prediction is easy to explain away after the fact with an added mitigating factor. The technique holds its value as classical history and as symbolic vitality testimony. It gives you no death date.
This page provides a traditional vitality marker for comparison with the rest of the chart. It does not provide a prediction.
Hyleg and alcocoden: how they differ
In 'Umar's method, the hyleg and kadukhudhah hold separate offices. The hyleg is the life indicator or releaser. The kadukhudhah, later called the alcocoden, is the qualified dignity lord associated with the planetary years.
The second search begins only after a hyleg qualifies. 'Umar tests the bound, domicile, exaltation, and triplicity lords of that degree and requires the selected lord to cast rays to it. The planet's source-defined condition then determines the applicable planetary-year unit. An indeterminate hyleg supplies no degree for this second procedure.
The alcocoden calculator applies that named year-giver procedure when a hyleg qualifies. The almuten figuris calculator runs a separate chart-wide dignity contest.
Sources and methodology
Implemented source: 'Umar al-Tabari, Three Books on Nativities I.4, translated by Benjamin Dykes in Persian Nativities II(2010), printed pages 7 to 10.
Author boundary: Ptolemy, Dorotheus, Valens, Paulus, and later authors preserve other candidate lists and qualifications. Their rules are historical comparisons on this page, rather than hidden inputs to the result.
House and testimony framework: 'Umar names angles, succedents, and specific houses but does not name a cusp algorithm. This implementation computes Porphyry quadrant cusps from the natal Ascendant and Midheaven and locates every candidate by degree. Witnessing uses whole sign conjunction, sextile, square, trine, or opposition. Dignity lords use Egyptian bounds and Dorothean triplicities. 'Umar names the triplicity lord without saying which of the three counts, and this calculator reads it as the sect lord alone. For a separate dignity score, see the essential dignities calculator.
Time key: Selection only. This procedure does not convert an arc or degree into years, so no timing key is applied.
Related Free Tools
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Prenatal Syzygy Calculator
Find your prenatal syzygy, the New Moon or Full Moon before your birth. See its phase, sign, house, and ruler with traditional context.
Sect Calculator
Determine your chart's sect (day or night), find your sect light, and discover which planets are your greatest benefic and greatest challenge.
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Frequently Asked Questions
What is the hyleg?
The hyleg is the life indicator or releaser in a family of historical length of life procedures. This calculator follows one named method, 'Umar al-Tabari's Three Books on Nativities I.4 in Benjamin Dykes's 2010 translation. It does not merge 'Umar with Ptolemy, Valens, or later Latin rules.
What does hyleg mean?
Hyleg is the later Persian-Arabic and Latin name for the traditional 'giver of life' or releaser. On this page that is historical terminology only. It does not mean the calculator measures life expectancy, medical health, or a death date.
How do you find the hyleg?
By day, 'Umar tests the Sun and then the Moon. By night, he begins with the Moon. If the lights fail, the prenatal lunation phase sets the order of the Ascendant and the Lot of Fortune, and the prenatal lunation is tested last. Each point must pass its own degree place rule and receive whole sign testimony from its domicile, bound, exaltation, or sect triplicity lord. The first point to pass becomes hyleg.
What is a hylegiacal place?
A hylegiacal place is a degree region where a candidate may perform the releaser's office. 'Umar gives different rules by candidate. This calculator locates his angles, succedents, and named houses with Porphyry quadrant cusps computed from the natal Ascendant and Midheaven. 'Umar does not name a cusp algorithm, so the result states this software framework explicitly.
Can the hyleg predict when I'll die?
No. Historical length-of-life techniques combined the hyleg with alcocoden planetary years and primary directions, but the rules vary widely and should not be used as lifespan prediction. Treat your hyleg as symbolic chart testimony. It supplies no timing clock.
What is the difference between the hyleg and the alcocoden?
In 'Umar's procedure, the hyleg is the life indicator and the kadukhudhah, later called the alcocoden, is the planet associated with the years. A qualified hyleg supplies the degree whose dignity lords are tested for the second office. If this calculator returns no qualified hyleg, it does not manufacture a degree for that next calculation.
What's the difference between hyleg and apheta?
Aphetes is a Greek term for the releaser, while hyleg comes through Middle Persian and Arabic transmission. They can perform corresponding functions, but the words carry different histories and the procedures attached to them vary by author. This page uses hyleg because it implements 'Umar's Perso-Arabic procedure.
Which houses can qualify?
The place test depends on the candidate. 'Umar allows the day Sun in the Ascendant, Midheaven, or 11th, and in the 8th or 9th when it is in a masculine sign. His opening rule requires the Moon to be angular or succedent in a feminine sign. Fortune and the prenatal lunation must be angular or succedent, while the Ascendant is its own place. This calculator applies those rules to Porphyry quadrant houses by degree.
How does sect change the calculation?
In day births, the Sun is tested before the Moon. In night births, 'Umar begins with the Moon. Sect also chooses the triplicity lord that can witness a candidate, and the natal engine computes Fortune with the sect appropriate formula. Each of these is a gate a candidate passes or fails, so sect changes which candidate the sequence reaches rather than adding weight to a tally.
Does the hyleg calculation use a timing key?
No timing key is applied. This procedure selects a qualified point and does not convert an arc or degree into years. Primary directions and distribution through bounds state their own time keys on their separate results.
Is the hyleg always the Sun or the Moon?
No. A light can fail its degree place rule or lack testimony from an eligible dignity lord. 'Umar then tests the Ascendant, Fortune, and prenatal lunation in the order set by the prenatal phase. Every fallback point must qualify independently, so the procedure can finish without a qualified hyleg.
Can my Ascendant be the hyleg if I'm born during the day?
Yes. After the lights fail, 'Umar puts the Ascendant before Fortune for a conjunctional birth and after Fortune for a preventional birth. The Ascendant must still receive testimony from an eligible dignity lord. It does not become hyleg automatically merely because the earlier candidates failed.
Can the calculator return no hyleg?
Yes. If every available candidate fails its degree place rule or lacks the required dignity lord testimony, the result is indeterminate under 'Umar's method. The indeterminate result records the procedure's failure to qualify a point as part of the calculation. Another author's procedure may reach a different conclusion because its candidate order and qualifying rules differ.
Save your hyleg with your chart context
Create an account to keep this result with your birth data, compare it with other traditional tools, and return to it when you explore timing.