Free Master of the Nativity (Oikodespotes) Calculator

Master of the Nativity translates the Greek office Oikodespotēs geneseōs. Its meaning and selection rule change by author. The surviving texts disagree about the Predominator, the dignity lord that receives authority, and the conditions that qualify a planet.

This calculator applies four named procedures independently. A planet selected by Pseudo-Porphyry does not replace a different result from Valens, George's reconstruction of Paulus, or Firmicus. A failed qualification or unresolved source branch remains visible as an indeterminate result.

Master, Joint Master, and Lord are distinct offices. Only the Pseudo-Porphyry comparison includes all of them. Valens and George's reconstruction of Paulus elect a Master, while Firmicus reaches a Master without first electing a Predominator.

Take the planet a method names and read it as the theme the chart keeps returning to. When several methods land on the same planet, start there. When they split, read each named planet in turn and keep track of which procedure produced it. Either way, five things are worth checking in order:

1. Sign. The sign colors the character of the agenda. A master in Capricorn runs a different life from a master in Pisces, even when both sit well.
2. House. The place tells you which arena the agenda plays out in. Master in the 7th puts the work in partnership. Master in the 10th puts it in public. Check which house framework the method assumed, since the four procedures do not share one.
3. Dignity. A master in its own sign or in exaltation reaches its agenda easily. A master in detriment or fall meets friction at every turn. Run the essential dignities calculator on the named planet itself.
4. Sect status. A master that belongs to the chart's sect, a day planet by day or a night planet by night, operates with the grain of the chart.
5. Aspects to the Predominator. Pseudo-Porphyry, Valens, and George's reconstruction of Paulus all elect from a Predominator, so the relationship between the two matters. A master that witnesses its Predominator by sign or by whole-sign aspect works with a clear line of authority. A master afflicted by malefics while averse to it works against one.

A master in poor condition does not cancel the agenda. It tells you where the friction comes from. If the named planet is also besieged between the malefics, the chart contests its own agenda, and the Joint Master and the Lord become more useful to read.

Divergence between the methods is readable material. A chart where all four converge behaves differently in practice from one where Valens withholds a Master and Firmicus points somewhere else entirely. Note which procedures agreed before you carry any single planet into a client conversation.

Pseudo-Porphyry. A qualified Predominator hands the Master office to its domicile lord and the Joint Master office to its Egyptian bound lord. The preferred light has to be effective and eastern, so a day Sun in the western 7th place fails the test, and both lights keep separate night branches beneath the exact horizon. The Lord is a separate procedure that starts from the domicile ruler of the degree-precise Midheaven sign, then checks a planet in the 10th place and a planet rising toward it from the 11th. Two planets in the same qualifying place stay indeterminate, because this first procedure supplies no tie rule.

Valens. The Egyptian bound lord of the Predominator is the proposed Master. It has to witness the Predominator and it cannot be setting in the 7th place, and failing either test leaves no qualified Master. The operative-degree alternative Valens introduces in the following chapter sits outside this result. Bounds throughout the calculator are the Egyptian set, so 12 degrees Libra belongs to Mercury, whose bound there runs from 6 degrees up to 14.

Paulus through Demetra George. George reads Paulus's compressed lists as a comparison of the domicile, exaltation, sect triplicity, and Egyptian bound lords. The source ranks rulership count but leaves the qualitative conditions unordered, so the calculator resolves a tie only when one candidate is no weaker than every peer on each comparable condition and stronger on at least one. Conflicting advantages stay indeterminate, and a leading planet averse to the sect light stays uncertain, because Paulus presses testimony without plainly requiring it.

Firmicus. The Master comes from the next zodiacal sign the Moon enters. The sequence skips Cancer and Leo, so neither luminary receives the office, and no house framework enters the selection at all.

Editions used. Pseudo-Porphyry, Introduction to the Tetrabibloschapter 30, through Demetra George's 2022 reconstruction in Ancient Astrology in Theory and Practice, volume II, with the attribution to Porphyry itself disputed. Valens, AnthologyIII.1, Robert Schmidt's 1994 translation checked against Mark Riley's 2010 translation. Paulus, Introductory Matters36, Schmidt's 1993 translation and Dorian Gieseler Greenbaum's 2001 translation, implemented through George's reconstruction. Firmicus, Mathesis IV.19, Jean Rhys Bram's 1975 translation with the Latin text controlling the transmitted rule. Whole-sign places carry every procedure except the Pseudo-Porphyry Lord branch, which takes the Midheaven from the chart's degree-precise MC.

These offices were used for character judgments and historical length-of-life procedures. The calculator reports the selection rules as historical doctrine. It does not calculate a death date or present a planetary office as a personal lifespan estimate.

The source history remains uncertain in places. The Pseudo-Porphyry attribution is disputed, Paulus's syntax leaves the force of testimony unclear, and the Firmicus passage has a corrupt continuation. The result cards state the edition and framework used so those limits travel with each output.

For the separate life-significator problem, compare theHyleg calculator. For the later year-giver procedure, see theAlcocoden calculator.