Spanish Monk. Placidus de Tito, 17th century. Creator of the Placidus House System. One of the most commonly used house systems today.

The most commonly used house system in Western astrology. There seems to be no particular reason for its popularity except that calculation tables have always been easily available. The system is based on a division of time rather than space as in most other systems. The times taken for each degree of the ecliptic to rise from the IC to the ascendant, and from the ascendant to the MC, are trisected to determine the cusps of houses 2, 3, 11, and 12. The cusps of houses 8, 9, 5 and 6 are opposite these. The Placidus system is defined only for latitudes between 66°N and 66°S.