Derived Houses

Definition

Derived houses is a technique for reading one person or topic inside someone else's chart. You take any house, treat it for the moment as a fresh 1st house — a "turned Ascendant" — and re-count the other eleven houses from there, giving you a whole twelve-house framework for whatever that base house stands for. So the 2nd house counted from the 7th (which lands on the actual 8th) shows your partner's resources; the 4th counted from the 10th (landing on the actual 1st) shows your employer's home. The same counting works for any pairing of houses.

In Tradition

In the Arabic-influenced medieval Latin and Renaissance horary tradition, derived houses are a central tool for questions about relationships between people — partners, family members, allies, or opponents who belong to a particular topic-house. Hand notes the technique had taken close to its modern shape by Bonatti's time, though Greek-era astrologers used it less explicitly. Modern Western astrologers keep the method mainly for horary and for concrete event-questions, finding it less useful for psychological house meanings.

In Practice

To use the method, an astrologer picks the topic-house, treats it as a new 1st, and counts the standard house meanings forward to reach the house they need. Common moves: the 2nd from the 7th (the actual 8th) for a partner's money; the 3rd from the 10th (the actual 12th) for an employer's siblings; the 10th from the 4th (the actual 1st) for a parent's career; the 5th from the 5th (the actual 9th) for the children's creativity. The technique is essential in horary — the branch that answers a question from a chart cast for the asking moment — for anything hinging on two parties: debts (Masha'allah's "second from the seventh" formula in On Reception Chapter 6), a king's expectations (the 11th as the 2nd from the 10th), or the wives of partners (the 7th from the 7th). Bonatti closes his First House chapter with twelve derived-house meanings, one per pairing. Modern natal astrologers use it cautiously, since so many meanings can outrun what a single chart can carry.

Historical Origin

Hand's RH editorial footnote to Bonatti's First House chapter observes that "the use of derived house meanings had already assumed something like its modern form by Bonatti's time," with Greek-era astrologers using it less explicitly. Bonatti's cluster of twelve derived-house meanings (Liber Astronomiae, Tractate II, Pars III, Ch. V) consolidates the medieval Latin systematization. Masha'allah's On Reception Chapter 6 (Dykes 2008) gives the second-from-Xth formula plainly. Sahl ibn Bishr's On the Questions carries the doctrine forward from the Dorothean baseline through Umar al-Tabari's Arabic.

Further Reading