If you watched the Sun move against the background of the stars for a whole year, it would trace a large circle in the sky, called the ecliptic.
The zodiac is a thin band of the sky along which its 12 constellations form a celestial path. The Zodiac wheel is divided into 12 signs, each 30 degrees long and begins in Aries, the spot on the ecliptic where the Sun is on the first day of spring.
Across the starry sky
The word Zodiac means 'circle of animals' and derives from the Greek 'Zodiacus', meaning little creatures. This is not a totally accurate representation as Zodiac symbols include humans, mythical creatures, animals, water-dwellers and the lifeless, unsentient scales, but then the origins of the constellations are lost and these could be simplified symbols.
The emergence of Sun-sign astrology
The constellations of the Zodiac acquired significance because the stars maintained their patterns while planets moved among some of them. No one can say when this started, for the naming of the old constellations predates recorded astrological history.
In all forms of astrology, the Zodiac plays a vital role, but it is in Sun-sign astrology where there is sometimes a danger of confusion and marginalising of the majority of signs. In 1930, R.H. Naylor invented Sun-sign astrology as a way to include all of his column's readership in his horoscopes. He decided to write a piece for every person born, dictated by when the Sun passed through each particular Zodiac sign, and so he invented the 12-part daily horoscope.
Zodiac or Sun?
When you say you're an Aries, this is not actually your Zodiac sign. What you are actually saying is that you were born at a time of the year when the Sun is in the Zodiac sign of Aries.
The different facets of the Zodiac
The signs of the Zodiac were initially a way of following the planets through the sky, but now they are seen as the main characteristics of every living person on earth.
The influence of the Sun
Sun-sign astrology - based on the assumption that the sign the Sun falls into on your birthday is the First House - is relatively new, gaining prominence in the 20th century.
The Zodiac sign or star sign in which the Sun appears is given much more importance in modern astrology than it was in ancient times. Then, there was a more geocentric approach and each planet signified a particular area of life shown in the individual's birthchart.
Most people today know what their Sun sign is because of horoscope columns.
Here comes the Sun
Your Sun sign shows your essential personality, your ego and will-power. It represents the core of your potential and your individuality. Some personality keywords for the Sun in your chart are: self-reliant, dictatorial, courageous, successful, overconfident, strong, affectionate, authoritative, egotistical, leader, and creative.
The planetary rulers of signs
Obviously, not only the Sun travels through the Zodiac signs and each of the planets of the Solar System moves through the signs at different speeds. For example, the Moon enters a new sign about every two and a half days, whereas Saturn stays for more than two years in each of the 12 signs.
The 12 signs are all ruled by a planet and when the ruler falls into its traditionally associated sign, the energy is expressed in an easy, straightforward way. Your personal birthchart will probably not have many planets located in the sign they rule and you will need to take time to interpret the planet-sign relationship.
Origins of astrology and the Zodiac
Astrology finds its origins in Ancient Babylon, where it was first noted that the stars in the sky relate to the passing of the seasons. Basically a farmer's almanac, this practice evolved further in Ancient Greece and adopted mythical associations with Pythagoras' concept that the heavens moved.
By 200 AD, astrology was firmly established and it was then that Claudius Ptolemy, an Egyptian astronomer, produced Tetrabiblos, which many consider the most impressive and definitive book on astrology ever written.
The mythology attached to each of the Zodiac signs has accumulated from various sources - from the Greek 'Zodiacus' to the deities of the Egyptians, from Arabic texts to the discovery of modern planets. Over the last 3000 years, the lore surrounding astrology has expanded to create distinct characters for each of the Zodiac signs, allowing practitioners to define each by polarity, triplicity, element and even night and day.