Aries: March 21 - April 20 The first sign of the Zodiac, Aries symbolizes new beginnings. Arians tend to be aggressive and direct in expressing themselves, and are happiest when they can get something started and lead the way. Their key phrase is "I am." Ruled by the planet Mars, this fire sign is adventurous, impulsive and full of energy. When first meeting the "ram," one's impression is of someone who's exciting, vibrant and extremely talkative.