The 1st house corresponds to a fire sign and is therefore a house of dharma (duty or life purpose).
Dharma, birth, personal appearance, well-being, fame, character, disposition, tendencies, prosperity, strength, longevity, health, will power, conduct, dignity, self-esteem, face, head, happiness, early childhood, and start in life.
The 1st house is extremely important, since it is the distinguishing factor between all the people born on the same day. It Is the most personal part of a horoscope. It shows how one will be received by the world, whether one can be recognized for his or her accomplishments and gain fame or status. It is the personality, one's temperament, disposition, and tendencies. It reveals a person's confidence, self-esteem, and self-love.
The planet ruling the 1st indicates the nature of the personality and one's tendencies to a large extent. If the first house happens to be Libra, which is owned by Venus, then the person may be artistically inclined, romantic, passionate, etc. If the first house is Capricorn, then Saturn is affecting the disposition and the person will be of a serious temperament, inclined towards business or career matters.
The first house is an auspicious house, a good house. Wherever the ruler of the first is placed will be an area of vitality and interest. Also, the affairs of that house will flourish. However, the nature and condition of the planet and signs involved must be considered. Mars or Saturn will not produce the same benefits as Venus or Jupiter, and as malefics they may actually cause harm. Regarding signs. Mercury as ascendant lord in Virgo would be completely different than in Pisces. In Virgo. Mercury is exalted and gives excellent results, while the opposite is true in Pisces, where it is fallen. Further, if the planet considered is aspected by several malefics, it cannot give good results. The key in astrological work is to consider the numerous influences involved in any issue.
If the ascendant lord is placed in an auspicious house, then 1st house significations likewise flourish.
The karaka, or Indicator, of the first house is the Sun.
Retrograde lord of 1st house — it is harder for such a person to open up, show his talents, he needs more time for this than others. As a rule, such people lack self-confidence, but if they work on themselves and overcome this, they can become very successful.
Source: «Ancient Hindu Astrology for the Modern Western Astrologer» by James Braha