In order to give fuller interpretation to the Zodiac Signs, ancient astrologers subdivided each Sign into periods of approximately ten days. These divisions are known as the "decans" or "decantes" and cover modifications of individual traits, attributed to minor planetary influences, which temper or blend with the ruling influence of the period. The ten-day spans are somewhat arbitrary in order to allow for the five (and sometimes six) extra days in the year beyond the 360 days required for the thirty-six decans. According to accepted prodcedure, these days have thus been added to form various six-day periods instead of five. The earliest records of decans have been found inside coffin lids dating from the Tenth Egyptian Dynasty around 2100 B.C. Decans are also mentioned in the Babylonian Enuma Anu Enil, which dates approximately four centuries later. The root of the word "decante" is Greek in origin and means "ten days apart."

The planetary influences described under the decans are valuable in "shading" the traits of many individuals, but are generally subordinate to the stronger characteristics associated with the primary Zodiac Sign. In some people, the traits of the decans may only be slightly traced...in others, they are very marked. As a general rule, the primary Sign of an individual details his or her characteristics with what can be surprising exactitude, but where such individual traits may seem at variance with the accepted patterns of the Sign, then the answer may be found in that person's decan. A study of the decans may also reveal hidden factors to which a person may be susceptible, even though his or her major traits are fully delineated under his or her primary Sign.

The First Decan of Aries is also known as the Aries Decante and the "Week of the Child." As the fiery head of the Zodiac, this Decan embraces Mars, the ruling planet of Aries, as its prime influence. Thus, this First Decan is the most typical of its native Sign, meaning that individuals born during this period will possess the firm and assertive disposition which marks the drive associated with Mars. There is also an abundance of energy connected to this Decan, which can result in many ego clashes if the tendency to "come on too strong" is not kept under control. Indeed, many may feel somewhat threatened by natives of this First Decan who should strive to "tone down" some of the inherent dynamism if more satisfactory interpersonal relationships are desired. Nonetheless, such self-assertiveness can prove useful when this Aries subject is cast in the role of manager or coach, for example. These natives are constantly "on the go" and may "burn the candle at both ends" until they finally realize that, in order to survive, they must become more cognizant of the fact that they are, after all, only human. The influence of Jupiter (the secondary planet which governs this Decan) adds brilliance to the Aries nature, but any tendency toward triviality will weaken this trait. The First Decan of Aries is indicative of a fearless character, but one which should guard against becoming too headstrong. Impatient with a fierce sense of right and wrong, the passions of this Decan are notoriously strong and the individuals who fall under its jurisdiction are very physical. In addition, their word is their bond. Of all Aries natives, it is those governed by this Decan who are the most idealistic, romantic and restless. As such, they need to learn how to pace themselves in order to avoid early "burnout." The motto of the First Decan of Aries is "Action."

The constellation associated with this Decan is Triangulum (The Triangle). Based upon an abstract principle rather than a myth, this small and faint group of stars extends just South of Andromenda. Despite its lack of distinction, Triangulum was well-known to the Ancients and, because of its similarity to the Greek letter delta, was sometimes called "Delta" or "Deltotum." Triangulum has been associated with the delta of the River Nile and has also been connected with the Island of Sicily, which is shaped like a triangle. The Ancient Hebrews named this constellation in honor of a triangular musical instrument.

The Second Decan of Aries is also known as the Leo Decante and the "Week of the Star." The influence of the Sun, the secondary planet governing this Decan, can induce interesting differences but chiefly makes for a person possessed with much individual zest for originality. This secondary planetary influence also provides generosity, nobility and leadership to the aggresive trait inherent in the Mars temperament. Thus, this Decan is generally comprised of an excellent combination of influences with an immense potential for initiating ideas, discoveries and inventions of a new, daring and unique nature. While Aries supplies dynamism and courage, Leo ensures that these subjects will continue to "plug away" until they meet with success. In addition, this Second Decan of Aries has no tendency to go off "half-cocked." The Sun adds warmth and brightness to this Decan, coupled with a steady flow of both mental and physical energy. These Aries natives usually have a broad and beaming smile, together with a generally friendly countenance and manner. In addition, they may dress and groom themselves in something of a colorful...even showy...fashion and are most dramatic in expressing what they have to say. Regardless of chronological age, these subjects remain forever young at heart, able to get along well with others and can easily identify with those around them. There are, however, negative factors associated with this Decan. The dignity and magnetic qualities of the Sun may give way to vainglory, if the aggressive nature of Mars is allowed to rule. Romance, admiration, gratification and entertainment are of great importance to this Decan. Such individuals want the very best in just about everything and expect appreciation and recognition for their efforts. Fiercely protective, their children are of paramount importance to those individuals who fall under the jurisdication of this Decan. Born performers who seek out the spotlight and crave applause, these Aries subjects would find it difficult to go through life without a partner. The motto of the Second Decan of Aries is "Dominion."

The constellation associated with this Decan is Eridanus (The River). The heavenly source of Eridanus lies immediately to the West of Rigel in Orion and flows Southward, until it reaches its mouth in Achernar near the South celestial pole (a very bright star which is seldom seen from the Northern Hemisphere). This constellation has been seen as a river since ancient times. In mythology, Eridanus was a Greek River God associated with the Euphrates, Tigris and Nile. When Phaethon was struck down by Zeus for mishandling his father's chariot of the Sun, he fell into the River Eridanus, whose sisters were turned into Poplar trees for encouraging him.

The Third Decan of Aries is also known as the Sagittarius Decante and the "Week of the Pioneer." The influence of the Jupiter, one of the secondary planets governing this Decan, can induce interesting externalized characteristics and personality differences but chiefly makes for a person who will be interested in mental matters. Here, the influence of Venus (the other secondary planet governing this Decan) tempers the Aries nature, but allows it to become rash and headlong, ready to adopt any cause because of sentimental reasons. This Decan of Aries denotes a pleasure-seeking character which should be controlled. Cultivation of the sincerity and generosity which Jupiter supplies is all-important. Many individuals who fall under the jurisdiction of this Decan are dreamers...dreaming of faraway places, ancient mysteries and miracles. While the strong drive supplied by Aries is still apparent here, these natives are able to modify their approach so they can adjust from a "hard push" to a "soft pedal" if the former appears inappropriate or not working as well as it might. These are individuals who are better able to cope with resistance than natives governed by the other two Decans of Aries. On a personal level, those governed by the Third Decan of Aries tend to remain rather aloof from others and indeed, the environment in general. While this may appear to be indicative of a distant character who is difficult to get to know, being somewhat detached enables these Aries individuals to maintain better control of their tempers simply because they do not let as many things upset them. They protect their freedom and may lead a nomadic life. Liberty to come and go, coupled with the need for personal space, is essential to the health and happiness of this Decan. Its natives cannot abide employment, lifestyles or relationships that tend to restrict or confine. In short, these individuals love to travel and learn and are blessed with a wonderful sense of humor and general optimism. Particularly effective when helping others through problems and negative situations, natives of this Third Decan are pleasant to be around and will most probably spend their lifetimes...on and off...working to continue their education, both formally and informally. Of all Aries individuals, it is those ruled by this Decan who are most likely to approach love with a light attitude. Consequently, they find it much harder to settle down. The motto of the Third Decan of Aries is "Promotion."

The constellation associated with this Decan is Perseus (The Hero), a beautiful grouping of stars which straddles the Milky Way from Capella (in Auriga) to the constellation of Cassiopeia. Perseus may be seen in the Northern skies from July through March. In mythology, Perseus was the son of Zeus and a mortal woman named Danae. Perseus' most famous exploit was to kill the Gorgon Medusa...one of three sisters who were so terrifyingly ugly that one glance from their eyes turned the viewer to stone. Using the shield of Athene as a mirror, Perseus severed the head of Medusa whereupon, according to legend, Pegasus the Winged Horse sprang fully-grown from her spilled blood.