The Beginning of the Seventh House is the point known as the Descendant. This is the Western Horizon of the chart. If you are looking at a circular astrology chart it is the middle point of the arc on the right hand side. This is the point opposite the Ascendant (See the First House). As the Ascendant was our starting point and the emergence of a person or concept, so the Descndant is the opposite, it is the person meeting another or a concept reaching expression in the world. It is the point in the chart where the individual and the outside world meet each other.
The Seventh House is an extension of the seed of the Descendant. It is about relating to the outside world and the other person. It is quite the opposite of the First House which dealt with me and my emergence and needs. In our analogy it is the time our child has grown up and is ready to meet and settle down with another person. This is the House of Partnerships, it shows the area of life where we relate with another person. Besides the comfort and pleasure, what is a relationship for, but to make us grow as individuals and to change hopefully to kinder and better people. The area of the Seventh House allows us to see ourselves through another and in this way refine our character. The other person acts as a mirror for our attributes and faults and only through them can we change. Without them, our mirror, we cannot see anymore, either our beauty or our failings. This is why love is so powerful because we see ourselves in a completely different light as reflected back to us by the other person. As time progresses this reflection may not always highlight our beauty but nevertheless it will give us a feedback, through which over the years we will hopefully improve as an individual. This is the area of the Seventh House, learning through relationship. Infact people with planets in the Seventh House often project them on to their partner. Since this is the point where you and the other meet it is very easy to confuse your nature with that of the other person. Isn't it odd how people often attract exactly the same type of partner one time after another ? There is a lesson here that keeps getting repeated until the individual owns their nature and it is no longer necessary for that energy to come to them from the outside world.
This is an Air House and as such deals with concepts about relationships. What is right and fair, how should an individual be treated and what is Justice between people. The Seventh House is naturally ruled by and parallels the sign of Libra. The sign of Libra is the sign of the scales which shows us the idea of balance, fairness and the idea of two elements being in harmony.
A Person with many planets in the seventh house will focus their energies on relating to others and ideals of what is right and wrong and what is justice for the individual. They will come alive through relationship to another and not so much through being left to their own devices. Indeed they may be so heavily focused on the other person that they may lose themselves in the process. They may be very indicisive, as this House deals with the understanding of what is right and wrong, and this is often a great challenge as both sides of a case may seem equally valid.
With Mars in the Seventh House, a persons strength and energy will come out in the area of relationships. They may also be quite confrontational with the other person, alternatively they may disown their energy and project it on to another person and keep inviting in aggressive or abusive partners into their lives. With Saturn in the Seventh House there will be much work to do in relating to others. The person may only get married later in life after a lot of hard lessons in relationships.