The leader of the ancient Greek zodiacal system is Aries.

Aries, also known as the Ram, is the first constellation of the zodiac and is associated with the beginning of spring in the Northern Hemisphere. In Greek mythology, Aries represents the Golden Fleece, which was sought after by the hero Jason and his Argonauts.

Aries is a fire sign, which is associated with passion, energy, and enthusiasm. Those born under this sign are said to be confident, ambitious, and courageous, often stepping in as leaders in situations where others may hesitate.

The symbol for Aries is a ram, which is associated with strength, power, and determination. This animal represents the idea of pushing through obstacles and charging ahead with determination, regardless of the challenges that may lie ahead.

In terms of zodiac compatibility, Aries is said to be most compatible with fellow fire signs, such as Leo and Sagittarius, as well as with air signs, such as Gemini and Aquarius. On the other hand, Aries is said to have a difficult relationship with water signs, such as Cancer and Pisces.

Overall, Aries represents the start of a new cycle, the energy of new beginnings, and the determination to pursue one's goals with passion and ambition. As the first sign of the zodiac, Aries sets the tone for the rest of the astrological year and encourages us all to embrace new challenges and opportunities with courage and enthusiasm.