Mr. Garth has written the "Five Pillars of Fate" about 2nd century astrology and the Arabic lots. This means that the lot of fortune in your birth chart is also an Ascendant and there is another second house. The second house is what you do for a living and my birth chart has a second house of Capricorn but my fortune chart has a second house of Gemini. Gemini rules writing, teachers, wordplay, communications and twins. Capricorn is an earth sign ruling government, banks, time honored institutions, things from the earth such as gold or minerals, and older people especially men. The first house of your fortune chart rules you, your physical body and what type of person you are as well as your birth chart does. The ruler of both of my charts are in the fourth and the second house repectively, I mean the Ascendants. I am a person who loves books and words and also being at home. I took my last 2 vacations at home actually.
Still there is one more thing representing our life force and that is the lot of Spirit. Valens says to us from the second century "The Spirit and it's ruler govern matters concerning the soul, intellect and actions thourgh discourse and through giving and receiving." Here we are in all our glory or messed up condition as it may be. Mine is Gemini.
Fortune is our portion given to us, it is walking across the street and being hit by a bus because it is something that happens to you. You don't have any control over it. Spirit is ourselves deciding to cross the street. Our Sun Signs are us too more in the matter of personality. Our spirit is our style of doing things. Garth has his fingers on the astrology of Valens in an easy to understand book. The ninth house is the house of higher thought, of kings and queens, of where you are noble yourself, the ninth from the lot of fortune may tell you where you outdo yourself in royal style. I have Aquarius and Leo respectively. Dramatic and quirky. The tenth house of career will tell you public reputation and what you do and is along with the first one of the most powerful houses. The 10th house from the Lot of fortune and any houses in it have a lot to do with your success (or failure). I have Mercury in the second house as the tenth in my fortune chart and indeed Mercury rules my Lot of Exaltation. So it is how I see that this planet, more than any other, is what will power any success I will have in life. Astro.com will calculate the lot of fortune for you and then make a new chart with whole signs with the sign the lot of fortune is in as the first house. This new fortune chart is very enlightening. It is thought that if you were born at night then this lot is actually the Lot of Spirit as most reverse the formula for night births. Night people you count the degrees from the Moon to the Sun counter-clockwise and then count the same degrees from the Ascendant in the same counter-clockwise direction. I found this very difficult and actually mixed them up for many months. The ancients counted one two three and so can we, we can do it exactly as they did the Lots.
In some unclear way Neptune is tied up with your fortune, I don't understand it but cannot deny it is so. Jupiter is very important of course but Saturn figures karmically as signalling when we recieve what we are due.
We cannot decide our fortune but we can take the portion given to us and do with it what we can. Our fortune, like our talents, are given to us at birth.