In no other area of astrology is there so much mess and confusion than in the area of the so-called "houses". There are at least twenty or thirty different house systems or means of dividing the so-called "birthchart" into twelve segments of life activity.

The more commonly known house systems are: Whole signs(oldest), Equal House(1st century BC), Porphyry(3rd century AD), Alcabitus(6th century), Campanus(13th century), Regiomantus(14th century), Placidus(17th century), and Koch(20th century). Others include: Meridian(Midheaven), Topocentric, Morinus, Horizontal, Geodetic, Zodiacal, Svarogish, Krusinski, and so on.

In astrology, houses, mansions, or domains, are supposed to represent general areas of life activity. They are the grounding areas or arenas of expression for the planets. There are generally twelve houses, although in extreme northern or southern lattitudes there can be ten, depending on the house system used.

In modern astrology, two important points or "angles" are generally used in the construction of houses; the ascendant degree which begins the first house, and the Midheaven degree which starts the tenth house. At equatorial latitudes these two points are generally 90 degrees apart, but the further one moves north or south the greater or lesser the distance between them, resulting in uneven and sometimes intercepted(invisible) houses.

The most common house system in use today is the Placidus system named after Placidus de Tito of the 17th century. In this system, like most others, the ascending degree starts the first house and the midheaven degree starts the tenth house. The remaining houses are then trisected on a time arc basis rather than space. The problem is the houses distort or intercept in extreme latitudes.

It seems human nature always veers towards the more complex ideas or notions in any field, ignoring the truer and simpler ones. Originally, the words "houses" and "signs" were interchangeable or meant the same thing. A planet in Aries was also a planet in the house of Aries, so that in effect, there were no real houses as we know them today.

The artificial divisions we now know as houses were attempts by the early Greeks and the Hindus to measure strength "points" in the horoscope, which at some point in time(7th and 8th centuries AD) were construed or confused as means of dividing the birth chart. The ascendant and midheaven degrees and their opposites, for example, were definite power points or areas of intense focus, but not necessarily the beginnings of a house or quadrant.

In fact, there is no real basis for the astrological houses at all. They derive from a misunderstanding of the true nature of the Ascendant and Midheaven factors in astrology, the former representing the Earth or terrestial sphere, and the latter representing the Sky, Heaven, or celestial sphere. The Ascendant is planet Earth, and the Midheaven(MC) has as its source, the Earth's inner central sun. The IC(Imum Coeli) and the descendant are merely opposite or reflex points.

If any house system should be used at all, it should be the Whole Sign House system, where the ascendant sign becomes the whole first house and the others follow. The ascendant point can then fall anywhere in the first house and the midheaven point anywhere in the upper half of the chart. The Ascendant and Midheaven, in effect, become PLANETS, which is what they truly are, and because we live on planet Earth, it is the FIRST house or primary habitation. For a description of what the houses really mean, see here

The Whole Sign House system was used by the ancient Greeks and the Hindus(who still use it today). It is the oldest and simplest house system in existence, and immediateley eliminates the awful mess astrologers have made on the issue over the last 1300 years or so.

For a full explanation on whole sign houses see here.