Quadrant Systems

latin: quadrans

Definition

House-division methods in which the four chart angles (Ascendant, Imum Coeli, Descendant, Medium Coeli) all serve as house cusps: the Ascendant becomes the 1st-house cusp, the IC the 4th, the Descendant the 7th, and the MC the 10th. The four quadrants formed by the horizon-meridian axes are then subdivided into three intermediate house-cusps each, producing the twelve houses. Placidus, Regiomontanus, Koch, Campanus, and Porphyry are the most-used quadrant systems in modern Western practice.

In Tradition

All quadrant systems align the four angles with the four cardinal house cusps. Intermediate cusps differ by the scheme each uses to divide the quadrants: Placidus by trisecting time, Regiomontanus and Campanus by spatial divisions on the equator and prime vertical, Koch by trisecting Ascendant rising-time, Porphyry by equal ecliptic trisection between angles. Sasportas additionally uses the four quadrants as a chart-analysis tool, with each sector named development, expansion, expression, and transcendence.

In Practice

Practitioners choose a quadrant system based on tradition and purpose: Placidus remains the default for much modern Western, Hellenistic-revival, and horary practice; Regiomontanus is preferred by some traditional and horary practitioners following Lilly; Koch is preferred in parts of the European modern lineage. The chosen system determines the cusps of houses 2, 3, 5, 6, 8, 9, 11, 12 — and therefore which sign each cusp falls in and which planets fall in which houses for the bulk of the chart. Quadrant-system choice contrasts with the whole-sign system (where each sign IS a house, with no intermediate-cusp computation), and the choice is one of the foundational decisions in any chart-reading practice. Sasportas's quadrant-grouping framework (four self-themed quadrants — development, expansion, expression, transcendence) layers a chart-shape reading on top of whichever quadrant house-system the practitioner uses.

Historical Origin

Quadrant house-division emerges in the Hellenistic period as an alternative to whole-sign houses; Ptolemy, Porphyry, and Valens record early variants. The medieval Arabic and Latin traditions develop more elaborate quadrant systems; Placidus de Titis publishes his system in 1657, becoming the modern Western default. Sasportas's quadrant-grouping framework is documented in *The Twelve Houses* (Aquarian 1985), elaborated by Martin in *Mapping the Psyche* Vol 2 pp. 18-19.

Etymology

Origin: Latin. Meaning: quadrans = a fourth part; the chart divided into four quadrants by the two angular axes.

Further Reading