The 1st House relates to the sign of Aries and the planet Mars. It is about how you appear to other people. As we develop from birth, we learn how to present ourselves to others in order to get along as we need to. The sign of the Zodiac where the 1st House begins (the Ascendant or point on the Eastern horizon at the moment of our birth) indicates our tendencies for development of our personality. For example, a person with a Libra Ascendant or "cusp" of the 1st House would seek balance in his/her personality. He/she would tend to avoid confrontation and try to present a pleasing appearance.
The 1st House is also treated as a special point in the chart, so its aspects to other chart points is important and will reflect energies that enhance, interfere, etc with the personality. Planets and other points which appear in the 1st House will color the personality in their own ways. For example, the planet Mars in the 1st House will add its tendencies toward impulse, aggression and physicality. Having no planets in the 1st House does NOT mean you have no personality, but it suggests that you do not have a strong need to demonstrate or project your personality into situations.
Please consult the signs, planets and other chart points for their special effects by returning to the Astrology Chart page and clicking on the appropriate links.