The zodiacs, which in case you're a bit confused, are what this is about.  They were started by the Greeks (surprise, surprise) and tie into their legends.  Zodiac comes from the Greek word zodiakos, which plainly means, circle of animals.  'The Zodiac' is a band from the sun to Earth as we travel around it.  That 'band' in astrology is divided into twelve equal parts (so no 28 days on one part and 31 on another).  If you ask me, the Greeks were a bit more logical in that regard. 

            Aries was known as the first zodiac.  It starts March 21^st and ends on April 20^th.  It is the also known as the Ram.  The myth behind it (how it got in the stars) is that Phrixus and Helle were fleeing Hera on the back of a Ram given to them by Nephele.  Helle fell off as they were crossing the sea and drowned but Phrixus survived and sacrificed the bull to Zeus.  Zeus placed the bull in the sky.

            Aries is one of the most selfish signs (hey nothing against you, the Greeks made it up) and is also quick tempered.  They are also very courageous, determined, and go right to the point.

            Taurus is next and their 'month' lasts from April 21^st to May 21^st.  Taurus is supposed to be a Bull (Ive never seen the resemblance as with most of these) and is either one of Zeuss many disguises or one of his illegitimate son's sons.  In the son's son idea, Minos had a son with a head like a bull that was slain by Hercules.

            People who are Taurus are supposed to be patient and dependable but well, rather boring.  They stick to their routine but can be trusted with almost anything.

            Gemini is next and is the first that doesn't represent an animal.  Gemini is supposed to be twins (although the Arabs said it was two peacocks).  In Greek Mythology, Leda gave birth to a set of twins from Zeus and a set from her mortal husband.  The two boys (one from each set) grew up as brothers and when the mortal (Castor) died Pollux was devastated.  He asked Zeus to let him die so he could be with his brother and a touched Zeus put them together forever in the sky as a sign of brotherly love.  It is set between May 22^nd and June 21^st.

            Gemini's are said to be very moody, quick to change from one thing to another.  They are great sources of information, be it fact or gossip, but don't always think deeply about what they are doing or saying.

            Cancer is next and no I don't mean the disease.  I mean the crab constellation.  Hera sent the crab when Hercules was doing his twelve tasks and it pinched his foot.  Hercules then smashed it and Hera put it in the sky.  The Greek year started between June 22^nd and July 22^nd, when Cancer is.

            Cancers are said to be over-emotional though very imaginative and sympathetic.  They are often self-pitying and unforgiving although protective.

            The Lion, Leo, lasts from July 23^rd to August 23^rd.  The Lion represents the Nemean Lion that Hercules fought.  The Nemean Lion had skin no weapon could pierce so Hercules strangled him and used the skin as armor.  Zeus put the Lion in the sky in Hercules honor.

            Leo's are dramatic and broad-minded but they still are often plagued by jealousy.  The Lion is also quite vain though generous.

            The sixth sign is Virgo, the virgin or maid.  Not much is known about her other than she is related to a god.  The month lasts from August 24^th to September 23^rd.

            Someone who is Virgo is precise but sometimes over-cautious.  They can be quite modest but will often become to self-conscious.

            Libra follows Virgo and is right before Scorpio.  The only non-living sign of the Zodiac is there to keep the balance between its neighbors.  Libra is represented by scales and is between September 24^th and October 23^rd.

            Libra's are idealistic and charming romantics (err supposedly) but also indecisive, frivolous, and resentful.  They often look for a compromise though it is hard for them to make a commitment.

            The Scorpion or Scorpio is set between October 24^th and November 22^nd.  It is said to be the serpent from Genesis by many people.  It 'stung at the heals of Virgo' until separated by Libra.

            Don't let the myth let you down though.  Scorpio's aren't all-bad.  They are very committed and loyal and imaginative.  However, they can be untidy, self-pitying, and devious.

            Sagittarius or the Archer is said to represent centaurs, a much of time drunken race of half men, half horse, stargazers.  They were also good archers (thus the name).  Sagittarius's time lasts from November 23^rd to December 21^st.

            Sagittarius is optimistic and visionary although they can be lazy and never get around to carrying out their vision.  They are sincere most of the time but are likely to exaggerate.  They are irresponsible.

            From December 22^nd to January 20^th the zodiac sign is Capricorn or the Goat.  The goat has the hindquarters of a fish and is said to Pan who used to have the hindquarters of a goat but then swam for a long time in the Nile and adapted the fish legs.

            Capricorns are reliable hard workers but are often pessimistic. 

            Aquarius is from January 21^st to February 19^th.  This water bearer was named Ganymedes and Zeus elected him cupbearer to the gods instead of Hera's daughter, Hebe.  Hera, hearing of this, banished him to the sky.

            Aquarius is original and independent often becoming rebellious.  They are very progressive thinkers though quite unpredictable.

            The last sign is Pisces, the fish.  It was caused when two gods, Aphrodite and Eros were fleeing another god, Typhon.  The mother and son hid by becoming a two-headed fish.  They are near Pegasus in the sky.

            The fish is artistic but this often leads to them being impractical.  The can be vague but still sympathetic.  They often become guilt ridden.

            So that's the twelve signs, and I by no means meant anybody any offence.  I was just stating some older cultures believe.  There is also something called the cuts which is a period between 2 and 5 days at the end of each 'month' where the person born then may have traits from both signs.