This article records tradition as it has been passed down and reported. Its sources are not yet part of the atlas's verified catalogue.
The practice of assigning a family relationship to a specific planet and house did not originate with Lilly's seventeenth century textbook. Chris Brennan's documented survey of Hellenistic astrology traces the underlying logic, planets grouped into a day sect and a night sect, each sect claiming certain relationships and certain houses as its own, back to the Hellenistic astrological tradition of the early centuries of the common era, centuries before any English language handbook restated the system.
That documented earlier origin matters for how an entry is written, because the sect based reasoning behind a significator assignment, why the Sun and Saturn together signify the father rather than some other pairing, is not an arbitrary later convention but a specific, traceable piece of Hellenistic astrological theory, and Brennan's survey records how that theory was transmitted, and in places reworked, through the later Arabic and Latin astrological traditions before reaching a text like Lilly's own.
An entry draws on this documented history for the origin and internal logic of the significator system, keeping that historical record distinct from any one period's own working handbook, which states how the system was applied at one particular moment rather than where its underlying reasoning came from.