If your birth chart were a movie, the First House would be the lead character—you. While the Sun represents your core purpose and the Moon your emotional needs, the First House is the avatar you use to navigate the game of life. It governs your physical body, your mannerisms, your style, and your immediate "knee-jerk" reactions to the environment.
Technically, the cusp (beginning) of the First House is the Ascendant or Rising Sign. This is the exact degree of the zodiac that was rising over the eastern horizon at the moment you were born. Because the Earth rotates once every 24 hours, the Rising Sign changes every two hours, making it the most time-sensitive and personal point in your chart.
Why is it an "Angular" House?
The First House is one of the four "Angles" (along with the 4th, 7th, and 10th). Angular houses are power centers. Planets located here are like actors standing at the very front of the stage with a spotlight on them. They are loud, visible, and have a massive impact on your life. A planet in the First House becomes part of your identity—it "colors" your personality even more than your Sun sign sometimes.