The Firdaria
Persian planetary-period system — earliest surviving account al-Andarzaghar; fullest, Abu Ma'shar (9th c.)
The Firdaria assign fixed spans of years to the planets in a set sequence, in a different order for day and night charts, each span subdivided among all the planets. The earliest surviving account is al-Andarzaghar's; Abu Ma'shar gives the fullest and most influential one. They reached Latin Europe in the 12th century through al-Qabisi's Introduction to Astrology and Hugo of Santalla's Book of Aristotle, and Bonatti popularised them in the 13th.
What it measures
A ruling planet for each period of life, from a fixed order (Sun-first by day, Moon-first by night for the seven planets, with the lunar nodes appended), each period then divided into seven sub-periods.
Where practitioners disagree
- Where do the lunar nodes fall in the night sequence?
After Mars (ages ~39–44) on one reading, or elsewhere — the sources are not explicit
Bonatti's night passage is ambiguous; the common 'nodes after Mars' placement is a modern inference from it, not a statement he makes, and al-Qabisi omits Abu Ma'shar's night clarification.
This engine: We follow the documented day/night orders; the nodes are placed and left unsubdivided.
Sources
- Abu Ma'shar (trans. B. Dykes), Persian Nativities (9th c.)
- al-Qabisi (trans. Burnett, Yamamoto & Yano), The Introduction to Astrology