Astrologers created charts called birth charts or horoscopes. A horoscope is a diagram of the heavenly bodies showing the relative positions of the sun, moon, stars, and planets at a given time. An individual's chart shows the position of the planets in relation to the earth and the stars at his or her birth. A horoscope is illustrated by a circle. This circle is known as the ecliptic. The ecliptic is the plane on which the earth orbits around the sun in a year. It is divided into twelve sections, called the signs of the Zodiac. The Zodiac divides the calendar year into 12 sections, and then each section is represented by a sign. The signs of the zodiac include Aries, Taurus, Gemini, Cancer, Leo, Virgo, Libra, Scorpio, Sagittarius, Capricorn and Pisces. Astrologers assign every planet (including the sun and moon) with a particular sign of the Zodiac. This relationship depends on where that planet appears on the ecliptic at the time for which the horoscope is cast. Each planet or sign represents basic human drives, and each sign represents a set of human characteristics. Each of the 12 signs of the zodiac is believed to be associated with definite aspects of character, temperament, physiology, and aptitudes. Each sign of the Zodiac has a corresponding stone, metal, and symbol.