The 12 Houses of astrology are symbolic of the all the departments that make up human life. The planets and zodiac signs will manifest themselves most strongly in the sphere of life represented by the House in which they fall on your chart. Houses are not "energies" like the elements or planets, nor do they color the expression of energies like the zodiac signs do. The houses are WHERE these energies are most likely to manifest. The houses are the fields of experience, not the experience themselves.
The First House is commonly referred to as the House of Self. The cusp of the First House is the home of the Ascendant, the Sign which was rising on the eastern horizon at the precise moment of one's birth. By thinking of this in terms of sunrise and new beginnings, one begins to grasp the concepts of the First House. The new beginnings here are centered around the individual: the self and the attendant voyage of discovery which defines a person. Who are you? What will you become? How do you realize your best self? The First House speaks to the realization of one's ultimate potential. This process of becoming a unique individual is one of the greatest contributions we make to the world in which we live.
The distinct qualities which we possess are often referred to as personality. The First House addresses the individual, his or her comportment and approach to life. In other words, the sum total of one's being. This is the package we give to the world. The packaging itself, or our outer being, is also governed by the First House -- think the physical body and the way in which we present ourselves, and in particular, the head and face.
Early childhood is also ruled by the First House. Everything from our earliest steps to our view of the emerging world is considered here. How will we develop? What is our view on life? It all begins at the beginning (the First House) and serves to shape us for all time.
In sum, the First House speaks to the person we are becoming and will become, both internally and externally. It addresses our personality and presentation to the world, our essential qualities, approach to life, demeanor and basic sensibilities. The inner self and outer body are what the First House is all about.
The First House is ruled by the Sign Aries and the Planet Mars.