The Sign rising over the horizon at the time of your birth is called the Ascendant, or Rising Sign. This, the first house of the horoscope, changes approximately every two hours. Even twins born as little as five minutes apart could have different ascendants, which would make a real difference in their horoscopes and so in their personalities. The Rising Sign governs your outer personality and physical attributes. It represents your self-image and, to a considerable extent, how others see you. It also affects your health issues and the type of illnesses you may experience. The Rising Sign rules the first house, so its ruling planet is usually designated the ruler of the horoscope. Unless poorly aspected or otherwise weak in comparison with other important planets, such as the planet ruling your Sun Sign (the Sun-ruler), this ruling planet is the most important one in your chart. .